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Future climate presents conflicting implications for forest biomass. We evaluate how plant hydraulic traits, elevated CO2 levels, warming, and changes in precipitation affect forest primary productivity, evapotranspiration, and the risk of hydraulic failure. We used a dynamic vegetation model with plant hydrodynamics (FATES-HYDRO) to simulate the stand-level responses to future climate changes in a wet tropical forest in Barro Colorado Island, Panama. We calibrated the model by selecting plant trait assemblages that performed well against observations. These assemblages were run with temperature and precipitation changes for two greenhouse gas emission scenarios (2086-2100: SSP2-45, SSP5-85) and two CO2 levels (contemporary, anticipated). The risk of hydraulic failure is projected to increase from a contemporary rate of 5.7% to 10.1-11.3% under future climate scenarios, and, crucially, elevated CO2 provided only slight amelioration. By contrast, elevated CO2 mitigated GPP reductions. We attribute a greater variation in hydraulic failure risk to trait assemblages than to either CO2 or climate. Our results project forests with both faster growth (through productivity increases) and higher mortality rates (through increasing rates of hydraulic failure) in the neo-tropics accompanied by certain trait plant assemblages becoming nonviable.

Spatiotemporal patterns of plant water uptake, loss, and storage exert a first-order control on photosynthesis and evapotranspiration. Many studies of plant responses to water stress have focused on differences between species because of their different stomatal closure, xylem conductance, and root traits. However, several other ecohydrological factors are also relevant, including soil hydraulics, topographically driven redistribution of water, plant adaptation to local climatic variations, and changes in vegetation density. Here, we seek to understand the relative importance of the dominant species for regional-scale variations in woody plant responses to water stress. We map plant water sensitivity (PWS) based on the response of remotely sensed live fuel moisture content to variations in hydrometeorology using an auto-regressive model. Live fuel moisture content dynamics are informative of PWS because they directly reflect vegetation water content and therefore patterns of plant water uptake and evapotranspiration. The PWS is studied using 21,455 wooded locations containing U.S. Forest Service Forest Inventory and Analysis plots across the western United States, where species cover is known and where a single species is locally dominant. Using a species-specific mean PWS value explains 23% of observed PWS variability. By contrast, a random forest driven by mean vegetation density, mean climate, soil properties, and topographic descriptors explains 43% of observed PWS variability. Thus, the dominant species explains only 53% (23% compared to 43%) of explainable variations in PWS. Mean climate and mean NDVI also exert significant influence on PWS. Our results suggest that studies of differences between species should explicitly consider the environments (climate, soil, topography) in which observations for each species are made, and whether those environments are representative of the entire species range.

Leaf area to sapwood area ratio (AL/AS) influences carbon sequestration, community composition, and ecosystem functioning in terrestrial vegetation and is closely related to leaf economics and hydraulics. However, critical predictors of AL/AS are not well understood. We compiled an AL/AS data set with 1612 species‐site combinations (1137 species from 285 sites worldwide) from our field experiments and published literature. We found the global mean AL/AS to be 0.63 m2 cm−2, with its variation largely driven by growing‐season precipitation (Pgs), which accounted for 18% of the variation in AL/AS. Species in tropical rainforests exhibited the highest AL/AS (0.82 m2 cm−2), whereas desert species showed the lowest AL/AS (0.16 m2 cm−2). Soil factors such as soil nitrogen and soil organic carbon exhibited positive effects on AL/AS, whereas soil pH was negatively correlated with AL/AS. Tree density accounted for 7% of the variation in AL/AS. All biotic and abiotic predictors collectively explained up to 45% of the variation in AL/AS. Additionally, AL/AS was positively correlated to the net primary productivity (NPP) of the ecosystem. Our study provides insights into the driving factors of AL/AS at the global scale and highlights the importance of AL/AS in ecosystem productivity. Given that Pgs is the most critical driver of AL/AS, alterations in global precipitation belts, particularly seasonal precipitation, may induce changes in plant leaf area on the branches. Summary statement: In this study, we assessed global patterns and key predictors of leaf area to sapwood area ratio (AL/AS) and underscored the significance of growing‐season precipitation, soil pH, and tree density in influencing AL/AS variation and its impact on plant primary productivity. [ABSTRACT FROM AUTHOR]

The process of allocating resources to different plant organs in the early stage of development can affect their adaptation to drought conditions, by influencing water uptake, transpiration, photosynthesis, and carbon storage. Early barley development can affect the response to drought conditions and mitigate yield losses. A distinct behavior of biomass partitioning between two Spanish barley landraces (SBCC073 and SBCC146) was observed in a previous rhizotron experiment. An RIL population of approximately 200 lines, derived from the cross of those lines, was advanced using speed breeding. We devised an experiment to test if seedling biomass partitioning was under genetic control, growing the seedlings in pots filled with silica sand, in a growth chamber under controlled conditions. After 1 week, the shoot and root were separated, oven dried, and weighted. There were genotypic differences for shoot dry weight, root dry weight, and root-to-shoot ratio. The population was genotyped with a commercial 15k SNP chip, and a genetic map was constructed with 1,353 SNP markers. A QTL analysis revealed no QTL for shoot or root dry weight. However, a clear single QTL for biomass partitioning (RatioRS) was found, in the long arm of chromosome 5H. By exploring the high-confidence genes in the region surrounding the QTL peak, five genes with missense mutations between SBCC146 and SBCC073, and differential expression in roots compared to other organs, were identified. We provide evidence of five promising candidate genes with a role in biomass partitioning that deserve further research. [ABSTRACT FROM AUTHOR]

Eggplant (Solanum melongena L.) is an important traditional crop, cultivated worldwide. Olive mill wastewater (OMW) is an important olive oil extraction byproduct due to its high concentration of different valuable compounds. Three eggplant cultivars were evaluated under different concentrations of olive mill wastewater. Seedlings were treated with four OMW levels (control, 25% OMW, 50% OMW and 100% OMW). Eggplant cultivars expressed different physiological responses when irrigated with OMW at different levels. Many physiological parameters such as growth, stomatal conductance, transpiration, relative water content, relative growth rate, stem diameter and chlorophyll content were examined. It has been found that many of these responses were adversely affected when plants were irrigated with OMW. Unexpectedly, the water status of eggplants was not affected by the different levels of OMW as plants maintained transpiration rate similar to the control values. Our findings clearly suggest that the physiological responses of eggplant to OMW vary among cultivars. However, the ability of plants to absorb water were not affected by OMW. We recommend that the sensitivity of the eggplant cultivars to OMW be taken into consideration before irrigating eggplants with OMW. [ABSTRACT FROM AUTHOR]

Background: Fe toxicity often inhibits rice growth on acid sulfate soils in tropical coastal lowlands. Previous studies in plant physiology and breeding have focused on high‐Fe stress, but not on growth recovery after stress alleviation. Aims: The objective of this study was to elucidate the morphophysiological characteristics in rice growth recovery from high‐Fe stress. Methods: We evaluated the seedling growths of Taichung65 (T65) (Fe toxicity‐tolerant) and Ciherang (susceptible) in hydroponic culture, during the period of high‐Fe stress (250 mg Fe2+ L−1 for 12 or 18 days) and after stress alleviation. Results: The plant growth rate during recovery was negatively correlated with the leaf bronzing score (damage symptoms due to Fe toxicity) at the end of high‐Fe stress, which in turn was negatively correlated with the shoot Fe concentration. After 18‐day stress, T65 showed greater growth recovery than Ciherang, attributable to its higher net assimilation rate, higher transpiration rate (water uptake/green leaf area), and greater increase in total root length during recovery. In particular, T65 showed vigorous lateral root development in nodal roots that emerged during the stress period and vigorous growth of nodal roots that emerged during recovery. Conclusions: Our results suggest that tolerance to high‐Fe stress confers an advantage in growth recovery. It is likely that tolerance to Fe toxicity contributes not only to the maintenance of green leaf area at the end of stress but also to quick root growth recovery, leading to vigorous water uptake and high photoassimilation capacity after stress alleviation. [ABSTRACT FROM AUTHOR]

Indoor vertical farms can optimize light, temperature, humidity, and nutrient use, thus potentially maximizing crop growth and yield. However, the reported potential for enhanced crop growth and yield within these systems needs to be tempered against the understanding of the effects of this "forced growth"/optimal growth environment on "actual" plant performance to fully reap the benefits of these innovative vertical farming systems. We investigated the effect of calcium (Ca) on the production of strawberries in an indoor vertical farm system with varying photosynthetic photon flux density (PPFD). Fruit yield of plants fed with high Ca (9 meq·L21) increased by 42.3% when the PPFD was 422 µmol·m-2·s21; however, a subsequent increase to 572 µmol·m-2·s-1 resulted in a decline in fruit production. Plants treated with low Ca (5 meq·L-1) had a reduced yield and demonstrated no response to the PPFD. The observed increase in yield was associated with increased fruit production and total soluble solids. Plants exhibited 21.5% and 57.8% increases in the total dry weight when exposed to 422 and 572 µmol·m-2·s-1, respectively; however, Ca did not have any impact on this response. Independent of the Ca concentration, the photosynthesis rate increased by 16.1% and 22.2% when the PPFD increased to 422 and 572 µmol·m-2·s-1, respectively; however, the highest photosynthesis rate was recorded with 422 µmol·m-2·s-1 when the Ca level was 9 meq·L-1. High Ca-fed plants exhibited a reduction in Ca (217.1%) content in their fruits when exposed to 572 µmol·m-2·s-1, which was likely caused by a dilution effect attributable to increased fruit biomass. In contrast, shoot Ca increased when plants were given high Ca when the PPFDs were 422 and 572 µmol·m22·s21. The Ca concentration in shoots correlated with the increasing yield, and a higher Ca concentration was associated with the increasing transpiration rate and stomatic conductance. Shoot phosphorus declined when plants were exposed to increased PPFD, and phosphorus was lower when plants were provided with 9 meq·L21 of Ca; however, plants watered with low Ca solutions had more potassium. The shoot nitrogen content and micronutrient contents were unchanged regardless of the variations in PPFD or Ca. In summary, the favorable conditions for the cultivation of strawberry under controlled environments resulted in greater growth and fruit yield as long as Ca was provided at higher concentrations in the irrigation solutions (from 5 to 9 meq·L-1). We suggest that the higher demand of Ca that is necessary to satisfy the enhanced plant development observed in indoor farming systems may be connected to the role of Ca in the formation of new tissues, cell walls, and cell membranes. [ABSTRACT FROM AUTHOR]

This paper investigates an in situ, non-destructive detection sensor based on flexible wearable technology that can reflect the intensity of plant transpiration. The sensor integrates four components: a flexible substrate, a humidity-sensing element, a temperature-sensing element, and a self-adhesive film. It is capable of accurately and continuously measuring the temperature, humidity, and vapor pressure deficit (VPD) on the leaf surface, thus providing information on plant transpiration. We combined the humidity-sensitive material graphene oxide (GO) with a PDMS-GO-SDS flexible substrate as the humidity-sensing element of the sensor. This element exhibits high sensitivity, fast response, and excellent biocompatibility with plant interfaces. The humidity monitoring sensitivity of the sensor reaches 4456 pF/% RH, while the temperature sensing element has a sensitivity of approximately 3.93 Ω/°C. Additionally, tracking tests were conducted on tomato plants in a natural environment, and the experimental results were consistent with related research findings. This sensor can be used to monitor plant growth during agricultural production and facilitate precise crop management, helping to advance smart agriculture in the Internet of Things (IoT) for plants. [ABSTRACT FROM AUTHOR]

Land surface models (LSMs) play a crucial role in elucidating water and carbon cycles by simulating processes such as plant transpiration and evaporation from bare soil, yet calibration often relies on comparing LSM outputs of landscape total evapotranspiration (ET) and discharge with measured bulk fluxes. Discrepancies in partitioning into component fluxes predicted by various LSMs have been noted, prompting the need for improved evaluation methods. Stable water isotopes serve as effective tracers of component hydrologic fluxes, but data and model integration challenges have hindered their widespread application. Leveraging National Ecological Observation Network measurements of water isotope ratios at 16 US sites over 3 years combined with LSM‐modeled fluxes, we employed an isotope‐enabled mass balance framework to simulate ET isotope values (δET) within three operational LSMs (Mosaic, Noah, and VIC) to evaluate their partitioning. Models simulating δET values consistent with observations were deemed more reflective of water cycling in these ecosystems. Mosaic exhibited the best overall performance (Kling‐Gupta Efficiency of 0.28). For both Mosaic and Noah there were robust correlations between bare soil evaporation fraction and error (negative) as well as transpiration fraction and error (positive). We found the point at which errors are smallest (x‐intercept of the multi‐site regression) is at a higher transpiration fraction than is currently specified in the models. Which means that transpiration fraction is underestimated on average. Stable isotope tracers offer an additional tool for model evaluation and identifying areas for improvement, potentially enhancing LSM simulations and our understanding of land‐surface hydrologic processes. Plain Language Summary: Models help us understand where and how much water moves in our environment. For example, how much water moves through plants (transpiration) and how much evaporates from the soil. We usually check how correct these models are by comparing the combined evaporation and transpiration (ET) and water discharge, with field measurements. This approach can lead to errors, as models often disagree on how to split ET into plant transpiration and soil evaporation. Water isotopes (water molecules with different atomic weights) can help identify the right split in ET, but the lack of data and the difficulty in using this data in models has hindered their implementation. We used newly available water isotope data from the National Ecological Observation Network from 16 sites across the U.S. We followed this water through the models and compared their predicted isotope values of ET with observations. Models with good predictions will most likely have a correct split of ET. Analysis showed that for Noah and Mosaic models, the split of transpiration is too small on average. By following stable isotopes as a new tool for model evaluation, researchers can better identify areas for improvement, leading to more accurate simulations of water movement. Key Points: An isotope mass balance was applied to operational land surface models to evaluate their hydrologic partitioning of evapotranspirationIsotopic composition of water vapor in evapotranspiration from 16 National Ecological Observatory Network sites were compared to simulationsEvaporation and transpiration fraction were strongly correlated with simulation error; elucidating their over‐ and underestimation [ABSTRACT FROM AUTHOR]

Climate change is a situation that causes an increase in global temperature due to the increase in greenhouse gases in the atmosphere and the effect of natural processes. This temperature increase causes many environmental effects around the world. Two of these effects are ultraviolet-B (UV-B) radiation, a harmful type of electromagnetic light from the sun, and severe water shortages called droughts. In this study, we tried to determine how the wood structure (properties of libriform fibers and various mechanical properties) and plant photosynthesis parameters of Acer negundo and Acer pseudoplatanus species changes under two droughts (moderate and severe) and UV-B (low [8 kJ m−2 h−1] and high [12 kJ m−2 h−1]) stresses. Also, leaf gas exchange parameters (net photosynthesis, stomatal conductance, transpiration rate, and water use efficiency) were evaluated under these stressors. As a result, it was observed that fiber wall thickness decreased in seedlings exposed to both drought and UV-B radiation in both species. It was determined that plant gas exchange parameters decreased with drought stress but did not vary much with UV-B stress; the amount of plant transpiration decreased with the effect of drought and increased with the amount of UV-B radiation. The plant may have reduced transpiration to reduce the effect of drought stress and increased transpiration to use UV-B radiation for plant growth. [ABSTRACT FROM AUTHOR]

Evapotranspiration (ET) is a key component of the hydrological cycle, encompassing evaporation processes from soil and water surfaces and plant transpiration (Sun et al., 2017). Accurate estimation of ET is vital for effective water resource management, agricultural planning, and environmental monitoring (Gowda et al., 2008). However, the complex interactions between land surface conditions, vegetation, and atmospheric factors make direct measurement of ET challenging, leading to the development of various estimation methods. Remote sensing has become a widely used approach for estimating ET over large areas because it provides spatially comprehensive data (Xiao et al., 2024). Methods like the Surface Energy Balance Algorithm for Land and the Surface Energy Balance System utilise satellite-derived thermal imagery and meteorological inputs to calculate ET by analysing the energy exchanges between the land surface and the atmosphere. These methods are advantageous for their broad spatial coverage, making them particularly useful for regional to global scale studies. However, they require careful calibration and validation, and their accuracy can be affected by the spatial resolution of the satellite data and the quality of meteorological inputs. In addition to remote sensing, several other ET estimation methods are commonly employed. The Penman-Monteith equation is one of the most widely accepted methods, integrating meteorological data—such as air temperature, humidity, wind speed, and solar radiation— with biophysical properties of vegetation to estimate ET. This method has been validated extensively, making it a standard reference in ET studies. Empirical methods like the Hargreaves-Samani equation provide simpler alternatives that require fewer data inputs, making them suitable for regions with limited meteorological information but with a trade-off in accuracy. Direct measurement techniques offer highly accurate ET data, including lysimeters and eddy covariance systems. Lysimeters measure water loss directly from a soil column, while eddy covariance systems assess the exchange of water vapour and energy between the surface and the atmosphere. Despite their precision, these methods are limited by high costs, maintenance requirements, and their applicability to small-scale, homogeneous areas (Howell, 2005). Choosing the appropriate ET estimation method depends on the scale of the study, data availability, and the specific application. Remote sensing and models like Penman-Monteith offer scalability and broad applicability, while direct measurements provide precise data at localised scales. Integrating these methods can improve the reliability of ET estimates, enhance water resource management, and aid in climate adaptation efforts. [ABSTRACT FROM AUTHOR]

To study the impact of different varieties and planting densities on the transpiration rate of cotton in Xinjiang, a field experiment was conducted in 2022 in Wulanwusu, Xinjiang. Three cotton varieties (' Zhongmian 979' ' Zhongmian 703' and 'Guoxin cotton' ) and two planting densities (D1:22 plants·m−2 ; D2:11 plants·m−2 ) were establish for treatment. The transpiration rate was measured using a heat ratio stem flow meter, and the differences in daily average transpiration, daily transpiration change, and cumulative transpiration of cotton under different weather conditions (sunny, rainy) and time scales were compared to clarify the water consumption rules of cotton under different varieties and densities in northern Xinjiang. The results showed that: (1) planting density had a significant impact on the cumulative and daily transpiration rates of cotton population. The cumulative and daily transpiration rates of cotton increased significantly under D1 planting density. Under D1 planting density treatment, the cumulative and daily transpiration rates of three varieties were significantly higher than those under D2 planting density treatment (an average increase of 51.2%). (2) Cotton varieties had a significant impact on individual and group transpiration, with' Zhongmian 703' higher stem flow rate, daily transpiration rate, and cumulative transpiration than other varieties. (3) The transpiration of a single cotton plant showed a "几" shaped variation pattern on a daily scale. During the day (9: 00−21: 00), the transpiration was relatively stable, but there was still a slight stem flow at night due to root pressure. (4) The transpiration rate and amount of cotton decreased month by month from July to September. The daily transpiration curve of cotton in September gradually transitioned to a unimodal pattern, and the daytime transpiration starts later (10: 00) and ends earlier (20：00). (5) Accumulated transpiration had a positive correlation with both seed cotton yield and average leaf area, but it was not significant. [ABSTRACT FROM AUTHOR]

Background and Aims Leaf elongation is vital for productivity of Poaceae species, influenced by atmospheric CO2 concentration ([CO2]) and climate-induced water availability changes. Although [CO2] mitigates the effects of drought on reducing transpiration per unit leaf area, it also increases total leaf area and water use. These complex interactions associated with leaf growth pose challenges in anticipating climate change effects. This study aims to assess [CO2] effects on leaf growth response to drought in perennial ryegrass (Lolium perenne), tall fescue (Festuca arundinacea) and wheat (Triticum aestivum). Methods Plants were cultivated in growth chambers with [CO2] at 200 or 800 ppm. At leaf six to seven unfolding, half of the plants were subjected to severe drought treatment. Leaf elongation rate (LER) was measured daily, whereas plant transpiration was continuously recorded gravimetrically. Additionally, water-soluble carbohydrate (WSC) content along with water and osmotic potentials in the leaf growing zone were measured at drought onset, mid-drought and leaf growth cessation. Key Results Elevated [CO2] mitigated drought impacts on LER and delayed growth cessation across species. A positive correlation between LER and soil relative water content (SRWC) was observed. At the same SRWC, perennial grasses exhibited a higher LER with elevated [CO2], probably due to enhanced stomatal regulation. Despite stomatal closure and WSC accumulation, CO2 did not influence nighttime water potential or osmotic potential. The marked increase in leaf area across species resulted in similar (wheat and tall fescue) or higher (ryegrass) total water use by the end of the experiment, under both watered and unwatered conditions. Conclusions Elevated [CO2] mitigates the adverse effects of drought on leaf elongation in three Poaceae species, due to its impact on plant transpiration. Overall, these findings provide valuable insights into CO2 and drought interactions that may help anticipate plant responses to climate change. [ABSTRACT FROM AUTHOR]

Daily transpiration (Td) is crucial for both irrigation water management and increasing crop water productivity. The use of the remote-sensing-based two-source energy balance model (TSEB) has proven to be robust in estimating plant transpiration and evaporation separately for various crops. However, remote sensing models provide instantaneous estimations, and so daily upscaling approaches are needed to estimate daily fluxes. Daily upscaling methodologies have not yet been examined to upscale solely transpiration in woody crops. In this regard, this study aims to evaluate the proper image acquisition time throughout the day and four methodologies used to retrieve Td in almond trees with different production systems and water statuses. Hourly transpiration (Th) was estimated using the TSEB contextual approach (Th –TSEB) with high-resolution imagery five times during two diurnal courses. The tested methodologies were the following: the simulated evaporative fraction variable (EFsim), irradiance (Rs), reference evapotranspiration (ETo), and potential evapotranspiration (ETp). These approaches were first evaluated with in situ sap flow (T –SF) data and were then applied to the Th –TSEB. Daily T –SF showed significant differences among production systems and levels of water stress. The EFsim and ETp methods correlated better with measured T –SF and reduced the underestimation observed using the Rs and ETo methods, especially at noon in the severely water-stressed trees. However, the daily upscaling approaches applied in the TSEB (Td –TSEB) failed to detect differences between production systems. The lack of sensibility of Th –TSEB among production systems poses a challenge when estimating Td in canopies with discontinuous architectural structures. The use of ETp as a reference variable could address this issue as it incorporates various aerodynamic and radiative properties associated with different canopy architectures that influence the daily Th –SF pattern. However, more accurate ETp estimates or more advanced ETp models are needed. [ABSTRACT FROM AUTHOR]

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Due to the push for carbon neutrality in various human activities, the development of methods for producing electricity without relying on chemical reaction processes or heat sources has become highly significant. Also, the challenge lies in achieving microwatt‐scale outputs due to the inherent conductivity of the materials and diverting electric currents. To address this challenge, our research has concentrated on utilizing nonconductive mediums for water‐based low‐cost microfibrous ceramic wools in conjunction with a NaCl aqueous solution for power generation. The main source of electricity originates from the directed movement of water molecules and surface ions through densely packed microfibrous ceramic wools due to the effect of dynamic electric double layer. This occurrence bears resemblance to the natural water transpiration in plants, thereby presenting a fresh and straightforward approach for producing electricity in an ecofriendly manner. The generator module demonstrated in this study, measuring 12 × 6 cm2, exhibited a noteworthy open‐circuit voltage of 0.35 V, coupled with a short‐circuit current of 0.51 mA. Such low‐cost ceramic wools are suitable for ubiquitous, permanent energy sources and hold potential for use as self‐powered sensors and systems, eliminating the requirement for external energy sources such as sunlight or heat. [ABSTRACT FROM AUTHOR]

In subalpine fir wave forests, strips of dead and weakened trees occur perpendicular to the slope next to strips of healthy trees. To reveal the transpiration by weakened Abies veitchii trees exposed to increased atmospheric evaporative demand, we investigated the ecophysiological traits closely related to the growth and transpiration, comparing them with those of the healthy trees and saplings in the fir wave of Mt. Shimagare in central Japan. The transpiration rate (E) was investigated using sap flux sensors to measure heat pulse velocity and compared with the surrogate for the needle water demand, which was computed using a multilayered gas and energy transfer model (modeled E, Emod). Weakened trees exhibited smaller diameter growth and narrower sapwood than healthy trees, as well as lower heat pulse velocity compared with healthy saplings. However, needle‐level traits did not differ significantly between weakened and healthy trees. Needle water potential at midday was as negative as the needle turgor loss point, and the measured heat pulse velocity increased linearly with Emod but leveled off above a certain Emod value in weakened trees and healthy saplings, suggesting that trees restricted E to balance the needle water budget. Heat pulse velocity of weakened trees leveled off at Emod lower than that of healthy saplings, probably due to lower capacity for water supply to the needles. Restriction of E would occur less frequently but be necessary for both weakened and healthy A. veitchii on Mt. Shimagare to avoid hydraulic failure, sacrificing photosynthetic carbon assimilation. [ABSTRACT FROM AUTHOR]

【Objective】The physiological and biochemical mechanisms of Canna generalis Bailey seedlings in response to nitrate stress were studied in order to provide a basis for improving water eutrophication by planting Canna generalis Bailey. 【Method】Using Yunnan Canna generalis bailey as the material, hydroponic methods were used to study the nitrogen uptake, seedling growth, photosynthetic parameters, antioxidant enzyme activity as well as physiological and biochemical indexes of Canna generalis bailey under different nitrate nitrogen treatments.【Result】After treatment with 0 (CK), 10, 50, 100 and 150 mmol/L nitrate solutions for 5 weeks, the total nitrate uptake amounts of Canna generalis Bailey was 0, 411.7, 676.9, 554.6 and 516.4 mg/plant, the plant height increased by -0.27, 5.25, 4.25, 0.05 and -10.32 cm, and the fresh weight increased by 10.3, 32.7, 31.6, 20.3 and -11.0 g/plant, respectively. Within 5 weeks of hydroponic treatment, the photosynthesis and transpiration rates of 10 mmol/L and 50 mmol/L low concentration nitrate were significantly higher than those of the control. In the fifth week, the photosynthesis rate was about 11 and 15 times that of CK, and the transpiration rate was 4.3 and 7.5 times that of CK. Stomatal conductance and intercellular CO2 concentration remained high. The photosynthesis and transpiration rates of plants treated with 100 and 150 mmol/L nitrate solutions were at a low level, and the stomatal conductance was extremely low. The activities of SOD and CAT under 0 and 10 mmol/L treatments were relatively low, while those under 50, 100 and 150 mmol/ L treatments were significantly higher than those in the control. The activities of SOD and CAT under 50 mmol/L treatment were the highest and significantly higher than those under other treatments. POD activity was significantly higher at 50 mmol/L than that of other treatments within 5 weeks, and the lowest at 150 mmol/L, indicating that high concentration of NO3 - inhibited POD enzyme activity.【Conclusion】A lower concentration of 50 mmol/L nitrate can enhance the photosynthesis, antioxidant enzyme activity, and nitrate nitrogen absorption of Canna generalis Bailey, promoting its growth. However, a higher concentration of 100 mmol/L nitrate reduces the photosynthesis, antioxidant enzyme activity, and nitrate nitrogen absorption of Canna generalis Bailey, inhibiting its growth. [ABSTRACT FROM AUTHOR]

The responses of eco‐physiological processes such as leaf expansion, plant transpiration and senescence to soil water deficit have been reported to be genotype‐dependent in different crops. To study such responses in soybean (Glycine max. (L.) Merr.), a 2‐year (2017 and 2021) outdoor pot experiment was carried out on the Heliaphen automated phenotyping platform at INRAE in Toulouse (France). Six soybean cultivars (Sultana‐MG 000, ES Pallador‐MG I, Isidor‐MG I, Santana‐MG I/II, Blancas‐MG II and Ecudor‐MG II) belonging to four maturity groups (MG) commonly grown in Europe were subjected to progressive soil water deficit from the reproductive stage R1 for 17 and 23 days in 2017 and 2021, respectively. The fraction of transpirable soil water (FTSW) was used as an indicator of soil water deficit. Non‐linear regression was used to calculate FTSWt, that is, the FTSW threshold for which the rate of the eco‐physiological process in stressed plants starts to diverge from a reference value. According to FTSWt, the three eco‐physiological processes showed significant differences in sensitivity to water deficit: leaf expansion exhibits the highest sensitivity and the widest range (FTSWt: 0.44–0.93), followed by plant transpiration (FTSWt: 0.17–0.56), with leaf senescence showing the narrowest range (FTSWt: 0.05–0.16). Among six cultivars, regarding leaf expansion, Cvs Santana (FTSWt = 0.48 in 2017; FTSWt = 0.44 in 2021), Blancas (FTSWt = 0.51 in 2017; FTSWt = 0.48 in 2021) and Ecudor (FTSWt = 0.46 in 2017; FTSWt = 0.52 in 2021) in late MGs (I/II to II) exhibited higher tolerance to soil drying. Conversely, the cv. Sultana in the earliest MG (000) showed the highest sensitivity (FTSWt = 0.91 in 2017; FTSWt = 0.93 in 2021) to water deficit. However, concerning the FTSWt values for plant transpiration (0.17–0.56 in 2017; 0.19–0.31 in 2021) and senescence (0.05–0.16 in 2017; 0.06–0.16 in 2021), their range did not demonstrate a correlated trend with the MG. In addition, a negative linear correlation was observed between values of FTSWt of normalised leaf expansion at the whole‐plant level (NLE) and specific leaf area (SLA) measured on irrigated plants for both years. This suggests that genotypes with high values of SLA could be associated with higher tolerance of leaf expansion to soil water deficit. Such a non‐destructive phenotyping method under outdoor conditions could bring new information to variety testing process and provide paths for integrating genotypic variability into crop growth models used for simulating soybean eco‐physiological responses to water deficit across the plant, field and even regional scales. [ABSTRACT FROM AUTHOR]

• VPD and R g predominantly drive variations in tree-level transpiration. • Soil moisture availability did not limit tree-level transpiration. • Xylem sap flow exhibited a strong correlation with VPD, R g , and RH. • Significant correlation (P < 0.001) was observed between actual and potential transpiration. • Apple tree water usage was higher in the early season compared to mid- and late seasons. Understanding the environmental drivers and hydraulic dynamics of plants is pivotal for elucidating future water use strategies and refining precise irrigation techniques. In our investigation, we focused on the daily and seasonal fluctuations in sap flow (SF) using compensation heat-pulse techniques on 7-year-old 'Gamhong' apple trees. Predictions of stand transpiration were integrated using the Penman-Monteith grass reference evapotranspiration. Additionally, we measured leaf-level diurnal and seasonal stomatal conductance (g s), leaf water potential (Ψ Leaf), and transpiration rate (E) to explore the relationship between plant-level transpiration and orchard microclimate. Diurnal SF exhibited a pattern similar to global radiation (R g) and vapor pressure deficit (VPD), increasing in the morning with a peak in the afternoon and decreasing towards evening. Seasonal water use varied, with rates of 10.62 ± 0.282 L day-1 in early (May–June), 8.40 ± 0.222 L day-1 in mid- (July–August), and 5.96 ± 0.154 L day-1 in late season (September–October). Plant water consumption was influenced by weather conditions and evaporative demand driven by atmospheric VPD and R g. Clear and sunny days resulted in higher water use (10.23 ± 0.291 L day-1) compared to partially sunny but windy days (9.85 ± 0.32 L day-1) and cloudy/rainy days (5.37 ± 0.176 L day-1). Plant transpiration strongly correlated with VPD (R² = 0.565), R g (R² = 0.616), relative humidity (R ² = 0.623), and wind velocity (u, R ² = 0.684), while no significant correlation was observed with air temperature (T a , R ² = 0.19) or soil moisture status (Ψ soil , R² = 0.19). VPD and R g emerged as the primary drivers, with Ψ soil playing a minor role and not limiting tree-level transpiration. Leaf-level g s , Ψ Leaf , and E displayed similar diurnal trends. In our study, the integrated daily sap flow provided valuable insights into plant-water relations differently across growing seasons and its relationship with reference evapotranspiration (E o). The Penman–Monteith equation, using grass reference evapotranspiration indicated a positive correlation (R ² = 0.764, P < 0.001) between actual and estimated transpiration. However, the slope of the relationship differed significantly from 1.0, suggesting that E o per unit leaf area of grass corresponds to E 288 = E o /2.88 (L m-2 of leaf area d-1), which underestimated evapotranspiration. [ABSTRACT FROM AUTHOR]

This study aimed to investigate the evaporation (E) and transpiration (T) components of evapotranspiration (ETc), and the growth parameters of curly lettuce (Lactuca sativa L. cv. Caipira) grown under different irrigation treatments. The study was conducted in a Mediterranean-type plastic greenhouse located in Antalya, Türkiye, in the fall and spring growing seasons of 2020 and 2021, respectively. To assess the impact of water stress on ETc and its components, three different irrigation water levels [ I100 for full irrigation treatment (100%), I66 for 66% (I100×0.66), and I33 for 33% (I100×0.33)] were selected. Planted and unplanted pots were used to measure ETc and E independently. The values obtained from these measurements were used as inputs to calculate the evaporation that occurred in the soil under the crop canopy and plant transpiration. In the present study, T was determined indirectly from the difference of measured evapotranspiration and evaporation and estimated with the modified Hernandez-Suarez model (Te). The modified model for the different irrigation treatments showed high Te estimation performance. Evaporation from the soil in the planted pots (Es) was calculated by considering the canopy cover and soil water content. The study revealed that water stress significantly affected lettuce plant height, root length, cover percentage, leaf area index (LAI), number of leaves, fresh and dry head weights, and root weights (p<0.01). The study also investigated the relationship between Es/ETc , and LAI using an exponential method and established a strong nonlinear relationship in all irrigation treatments (R2>0.90). The modified model developed for different irrigation treatments in Mediterranean-type greenhouses can be used to predict lettuce ETc values with greater precision and to better understand the partitioning of ETc into its constituent components. [ABSTRACT FROM AUTHOR]

Anthropogenic increase in carbon dioxide (CO2) affects plant physiology. Plant responses to elevated CO2 typically include: (1) enhanced photosynthesis and increased primary productivity due to carbon fertilization and (2) suppression of leaf transpiration due to CO2‐driven decrease in stomatal conductance. The combined effect of these responses on the total plant transpiration and on evapotranspiration (ET) has a wide range of implications on local, regional, and global hydrological cycles, and thus needs to be better understood. Here, we investigated the net effect of CO2‐driven perennial ryegrass (Lolium perenne) physiological responses on transpiration and evapotranspiration by integrating physiological and hydrological (water budget) methods, under a controlled environment. Measurements of the net photosynthetic rate, stomatal conductance, transpiration rate, leaf mass per area, aboveground biomass, and water balance components were recorded. Measured variables under elevated CO2 were compared with those of ambient CO2. As expected, our results show that elevated CO2 significantly decreases whole‐plant transpiration rates (38% lower in the final week) which is a result of lower stomatal conductance (57% lower in the final week) despite a slight increase in aboveground biomass. Additionally, there was an overall decline in evapotranspiration (ET) under elevated CO2, indicating the impact of CO2‐mediated suppression of transpiration on the overall water balance. Although studies with larger sample sizes are needed for more robust conclusions, our findings have significant implications for global environmental change. Reductions in ET from ryegrass‐dominated grasslands and pastures could increase soil moisture and groundwater recharge, potentially leading to increased surface runoff and flooding. [ABSTRACT FROM AUTHOR]

Introduction: Dracocephalum moldavica L. is a herbaceous, annual plant from the Lamiaceae family that is native to Central Asia and domesticated in Central and Eastern Europe. Essential oil of this plant has antimicrobial and bacterial properties and has many uses in the pharmaceutical, cosmetic, food and perfumery industries. Lead stress in plants causes disturbances in mitosis, leaf chlorosis, decreasing of the vegetative and productive growth stages and reduces photosynthesis and enzyme activities. One of the effects of lead toxicity is due to the similarity of the structure of calcium ions and lead, and for this reason, lead ions disrupt many mechanisms related to calcium ions and prevent the activity of key enzymes.Photosynthesis is one of the most sensitive metabolic processes to lead toxicity, and several studies have reported the inhibition of photosynthesis under lead stress in various plants. Lead prevents the absorption of elements such as magnesium and iron. These elements play a role in the structure of chlorophyll and the oxygen-releasing complex in photosystem II. Heavy metals such as lead inhibit chlorophyll biosynthesis by inhibiting the enzymes gamma-aminolevalonic acid dehydrogenase and protochlorophyll reductase. Also the availability of different nutrients in the soil changes significantly under the influence of environmental stress so that using of vermicompost can be useful in stress condition as well as Jasmonate. Jasmonate is the final oxidation product of unsaturated fatty acids such as linolenic acid, that is effective in increasing the activity of plant defense systems under environmental stress conditions such as lead stress. In order to study the effect of pb (0, 100, 200, 300, 400 mg kg-1 soil) and jasmonate (0, 50, 100, 150 mmol l-1) on Dracocephalum moldavica L. under controlled conditions in soil enriched with vermicompost and without vermicompost an experiment designed and it was done under greenhouse conditions. Materials and methods: This test was done in a random factorial design with 4 repeats and indices including CO2 assimilation rate, transpiration rate, stomatal conductance, water use efficiency(WUE), PSII photochemical efficiency (Fv/Fm), photosynthesis quantum performance, electron transfer rate (ETR), were measured in vegetative and reproductive growth stages. Results and discussion: In the conducted study, it was found that CO2 assimilation rate, water use efficienty, stomatal conductance and Fv/Fm were significantly decreased as lead concentration was increased. Also jasmonate treatment significantly increased CO2 assimilation rate, water use efficienty, stomatal conductance and Fv/Fm in lead stress condition. So that plant treated with 400 mg kg-1 soil pb and 0 mmol l-1 jasmonate showed the lowest CO2 assimilation rate, water use efficienty, stomatal conductance and Fv/Fm while plant treated with 0 mg kg-1 soil pb and 150 mmol l-1 jasmonate showed the highest CO2 assimilation rate, water use efficienty, stomatal conductance and Fv/Fm. transpiration rate was significantly increased as well as increasing pb concentration so that plant treated with 400 mg kg-1 soil pb showed the highest transpiration rate. Also jasmonate treatment significantly decreased transpiration rate in lead stress condition. Vermicompost increased CO2 assimilation rate, water use efficienty, electron transfer rate (ETR) and significantly decreased transpiration rate in lead stress condition. Jasmonate reduces the destructive effects caused by stress on photosynthetic indicators such as the amount of chlorophyll and carotenoids and also increases the performance of photosystem II and consequently increases plant photosynthesis under stress conditions. It has been reported that methyl jasmonate can maintain the concentration of chlorophyll in the reaction center, thereby improving the speed of electron transfer and increasing the efficiency of photosystem II. In addition, jasmonate can prevent the severe reduction of stomatal conductance under stress conditions and increase the quantum efficiency of photosynthesis. In the response of plants to stress, jasmonates act as genes encoding inhibitory proteins such as theonine, hydroxyproline and proline, and in general, by activating defense mechanisms, they help the plant in reducing the absorption and accumulation of heavy metals. Organic fertilizers can also improve plant performance under environmental stress conditions. Vermicompost fertilizer increases porosity, increases absorption and retention of nutrients, improves ventilation, drainage and microbial activity in the soil. Conclusion: Having nutritious mineral elements and plant growth hormones can improve plant growth in the presence of environmental pollutants such as heavy metals by influencing the physiological characteristics. It can be said based on the results obtained lead stress decreased photosynthesis index through effect on electron transport chain and photosynthetic pigments while jasmonate treatment and Soil enriched with vermicompost can reduce the destructive effects of lead stress. So that using of jasmonate and vermicompost in lead stress condition Recommended. [ABSTRACT FROM AUTHOR]

ABSTRACT Water and soil nutrients are the vital ingredients of crop production, and their efficient uptake is essentially dependent on root development, majorly regulated by auxin. For a water‐loving crop like rice, how water availability regulates nutrient acquisition, additionally, how ambient nutrient level modulates water uptake, and the role of auxin therein is not well studied. While investigating the cross‐talks among these components, we found water to be essential for auxin re‐distribution in roots and shaping the root architecture. We also found that supplementing rice seedlings with moderate concentrations of mineral nutrients facilitated faster water uptake and greater nutrient enrichment in leaves compared to adequate nutrient supplementation. Additionally, moderate nutrient availability favoured greater stomatal density, stomatal conductance, photosynthesis, transpiration rate and water use efficiency when water was not limiting. Further, auxin supplementation enhanced root formation in rice, while affecting their water uptake ability, photosynthesis and transpiration causing differential mineral‐specific uptake trends. The present study uncovers the existence of an intricate crosstalk among water, nutrients and auxin signalling the knowledge of which will enable optimizing the growth conditions for speed breeding of rice and harnessing the components of auxin signalling to improve water and nutrient use efficiency of rice. [ABSTRACT FROM AUTHOR]

Avocado (Persea americana Mill.) cultivation has spread to many countries from the tropics to the Mediterranean region, where avocado crops commonly face water shortages and diseases, such as white root rot (WRR) caused by Rosellinia necatrix. The use of drought- and WRR-tolerant rootstocks represents a potential solution to these constraints. In this research, water relations and the morpho-physiological response of avocado 'Hass' grafted on two selections of R. necatrix-tolerant rootstocks (BG48 and BG181) were evaluated under well-watered (WW) and at two soil-water-availability conditions (WS, ~50% and ~25% field capacity). Under WW, scion water use was markedly affected by the rootstock, with BG48 displaying a water-spender behavior, showing higher water consumption (~20%), plant transpiration rates (~30%; Eplant) and leaf photosynthetic rates (~30%; AN) than BG181, which exhibited a water-saving strategy based upon a trade-off between leaf-biomass allocation and tight stomatal control of transpiration. This strategy did not reduce biomass, with BG181 plants being more water use efficient. Under WS, BG48 and BG181 exhibited a drought-avoidance behavior based on distinct underlying mechanisms, but increases in leaf mass area (~18–12%; LMA), and decreases in Eplant (~50–65%), plant hydraulic conductance (~44–86%; Kh) and leaf water potential (~48–73%; Ψw) were observed in both rootstocks, which aligned with water stress severity. After rewatering, photosynthetic rates fully recovered, suggesting some ability of these rootstocks to withstand water stress, enabling the 'Hass' variety to adapt to region-specific constraints. [ABSTRACT FROM AUTHOR]

In open fields, plants experience dynamic changes in environment, particularly radiation, temperature, wind, and humidity but their short-term responses have not been adequately characterized under natural conditions. In this study, we assessed causal effects of rapid radiation fluctuation on seven plant parameters in open fields of cotton and sweet corn canopies. The parameters are evapotranspiration (ET), canopy photosynthesis indicated by CO2 flux from air to canopy (FCO2), sensible heat energy flux (H), canopy conductance for water vapor (gcw), canopy surface temperature (Ts), shoot and leaf elongation rate, and stem diameter change. The energy and CO2 fluxes were measured with Bowen ratio/energy balance/CO2 gradient (BREB+) technique, using averaging time of 5 min. Shoot + leaf elongation and stem diameter change were monitored with position transducers using averaging time of 1 min. All parameters were all found to respond to change in radiation and transpiration within minutes or sooner. While radiation effects on canopy gas exchanges are expected, illuminating are the indirect but immediate effects on shoot + leaf growth and stem diameter change through radiation effects on transpiration and plant water status. A novel finding is that gcw also responded within minutes or sooner to radiation fluctuations and that FCO2 was related almost linearly to gcw. Results are discussed in terms of soil-plant-atmosphere continuum, and interpreted in terms of dynamic interactions between transpiration and plant water status. The clear inverse relationship between ET and elongation rate or stem diameter changes provides additional evidence supporting the validity of 5-min averaging for the BREB + technique. [ABSTRACT FROM AUTHOR]

Evapotranspiration (ET) is a vital process involving the transfer of water from the Earth's surface to the atmosphere through soil evaporation and plant transpiration. Accurate estimation of ET is important for a variety of applications, including irrigation management and water resource planning. The two-source energy balance (TSEB) model is a commonly used method for estimating ET using remotely sensed data. This study used the TSEB model and high-resolution unmanned aerial vehicle (UAV) imagery to estimate sorghum ET under four different irrigation regimes over two growing seasons in 2020 and 2021. The study also validated net radiation (Rn) flux through hand-held radiometer measurements and compared the estimated ET with a soil water balance model. The study outcomes revealed that that the TSEB model capably estimated Rn values, aligning well with ground-based Rn measurements for all irrigation treatments (RMSE = 32.9–39.8 W m−2 and MAE = 28.1–35.2 W m−2). However, the TSEB model demonstrated robust performance in estimating ET for fully irrigated conditions (S1), while its performance diminished with increasing water stress (S2, S3, and S4). The R2, RMSE, and MAE values range from 0.64 to 0.06, 10.94 to 17.04 mm, and 7.09 to 11.43 mm, respectively, across the four irrigation treatments over a 10-day span. These findings not only suggest the potential of UAVs for ET mapping at high-resolution over large areas under various water stress conditions, but also highlight the need for further research on ET estimation under water stress conditions. [ABSTRACT FROM AUTHOR]

Various ambient air contaminants can spread into the indoor building through air transport. With the additional generation of contaminants from indoor activities, indoor air quality (IAQ) has the potential to be polluted. Indoor air pollution incidents can occur anytime, which is difficult to predict. Therefore, it is necessary to take action to improve IAQ as early as possible and sustainably. The solution to sustainable remediation is using plants to apply phylloremediation, which functions as leaves and leafassociated microbial communities to reduce air contaminants. This study aims to provide new practical yet essential criteria for the sustainable operation of phylloremediation. This review is based on the latest results of a literature-based study. An analysis of the fundamental processes of plant life forms the basis for obtaining these criteria. The study emphasizes key criteria for phylloremediation encompassing the selecting plants with high transpiration and leaf-microbe synergy, and conducting maintenance by spraying water on leaves. These measures optimize efficiency and sustain the process for indoor air pollutant reduction. The final result summarises the new criteria for sustainable phylloremediation to maintain plant life. These essential criteria can be used for conducting experiments in empirical research, indoor design, and education for the community. [ABSTRACT FROM AUTHOR]

Terrestrial evapotranspiration (ET) is a vital process regulating the terrestrial water balance. However, significant uncertainties persist in global ET estimates. Focusing on the area between 60°, we performed an intercomparison of 90 state‐of‐the‐art ET products from 1980 to 2014. These products were obtained from various sources or methods and were grouped into six categories: remote sensing, reanalysis, land surface models, climate models, machine learning methods, and ensemble estimates. It is shown that global ET magnitudes of categories differ considerably, with averages ranging from 518.4 to 706.3 mm yr−1. Spatial patterns are generally consistent but with significant divergence in tropical rainforests. Global trends are mildly positive or negative (−0.10 to 0.37 mm yr−2) depending on categories but with distinct spatial variability. Evaluation against site measurements reveals various performances across land cover types; the ideal point error values range from 0.45 to 0.83, with wetlands performing the worst and open shrublands the best. Using the three‐cornered hat method, there are spatial differences in ET uncertainty, with lower uncertainty for ensemble estimates, showing less than 15% relative uncertainty in most areas. The best global ET data set varies depending on the intended use and study region. Distinct spatial patterns of controlling factors across categories have been identified, with precipitation driving arid and semi‐arid regions and leaf area index dominating tropical regions. It is suggested to include advancing precipitation inputs, incorporate vegetation dynamics, and employ hybrid modeling in future ET estimates. Constraining estimates using complementary data and robust theoretical frameworks can enhance credibility in ET estimation. Plain Language Summary: Evapotranspiration (ET) is an essential process where water transfers from the land to the atmosphere through evaporation and plant transpiration. However, substantial uncertainties exist across available global ET estimates produced by various models and methods. To date, we created the most comprehensive compilation of over 90 state‐of‐the‐art ET data products, including satellite‐based, land surface model, climate model, reanalysis, machine learning, and ensemble‐based estimates, covering 1980–2014 and ranging between 60°N and 60°S. These estimates show large differences in global ET magnitude, trends, and spatial patterns. We evaluated ET estimates against in situ measurements and found diverging performance across land cover types. We used statistical methods to quantify uncertainties in ET data products and found discrepancies in uncertainty distributions across methods. We also identified key factors driving spatial ET variability in each product category. Our analysis underscores the importance and opportunities for reducing the uncertainty in terrestrial ET and provides valuable insights for improving hydroclimatic predictions. Key Points: Global ET estimates show large discrepancies in magnitude, trends and spatial patterns across 90 state‐of‐the‐art data setsThere is no single best global ET data set suitable for all applications and locations, the choice depends on the intention and region of studyDominant controls on ET differ across categories spatially; constraining estimates via Budyko and novel hybrid modeling can enhance confidence [ABSTRACT FROM AUTHOR]

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The Journal of Experimental Botany has published guidelines for designing and interpreting drought experiments in controlled conditions. The guidelines aim to address flaws in research on drought tolerance and plant responses to water deficit, such as flawed experimental designs and inconsistent terminology. The recommendations include using precise terminology, accounting for genotype-environment interactions, considering whole-plant transpiration, and measuring soil and plant water status. The article discusses the challenges and pitfalls of designing and conducting plant stress experiments, specifically focusing on drought and heat stress. The authors emphasize the importance of considering factors such as spatial and temporal variations, feedback mechanisms, and the pot effect in experimental design. They recommend researchers to recognize and report the limitations of their experiments, assess complex environmental interactions, and account for genotype-by-environment interactions when interpreting data. The article also highlights the need for accurate measurement of plant stress levels and the selection of appropriate variables and time points for measurement. The authors aim to provide guidance for researchers in designing rigorous and reproducible stress experiments. [Extracted from the article]

To investigate the dynamics of stomata, transpiration, and photosynthesis under varying light intensities and CO2 conditions during leaf development, the light response and CO2 response of stomatal conductance (gsw), transpiration rate (Tr), and net photosynthetic rate (Pn) were observed for rice leaves at different days after leaf emergence (DAE). The results showed that (1) as photosynthetically active radiation (PAR) increased, leaf gsw, Tr, and Pn initially increased rapidly and linearly, followed by a more gradual rise to maximum values, and then either stabilized or showed a declining trend. The maximum gsw, Tr, and Pn were smaller and occurred earlier for old leaves than for young leaves. The gsw, Tr, and Pn all exhibited a linear decreasing trend with increasing DAE, and the rate of decrease slowed down with the reduction in PAR; (2) as the CO2 concentration (Ca) increased, gsw and Tr decreased gradually to a stable minimum value, while Pn increased linearly and slowly up to the maximum and then kept stable or decreased. The gsw, Tr, and Pn values initially kept high and then decreased with the increase of DAE. These results contribute to understanding the dynamics in gsw, Tr, and Pn during rice leaf growth and their response to varied light and CO2 concentration conditions and provide mechanistic support to estimate dynamic evapotranspiration and net ecosystem productivity at field-scale and a larger scale in paddy field ecosystems through the upscaling of leaf-level stomatal conductance, transpiration, and photosynthesis. [ABSTRACT FROM AUTHOR]

• Salt-coping strategies were studied investigating roots through a rhizoslide setup. • Different salt tolerance mechanisms were identified in the two halophyte species. • New Zealand spinach accumulated sodium and showed increased WUE at 100 mM NaCl. • Quinoa behaved as a sodium excluder with restricted growth at 100 mM NaCl. • Salinity affected both root architecture and plant transpiration. Soil salinity, root sodium concentration, and transpiration rate are important environmental factors impacting plant growth and productivity. This study investigates the salt-coping strategies of two plant species under varying salinity levels: New Zealand spinach species grown at three salinity levels (i.e., 0, 100, and 200 mM NaCl) and three varieties of quinoa, i.e., "Vikinga", "Dave 407" and "Red Head", grown with or without salt (i.e., 0 and 100 mM NaCl). The plants were grown on glass fiber sheets (rhizoslides) under controlled laboratory conditions. The relationship between transpiration rate, salinity, and root architecture was analyzed for each species. The root apparatus of New Zealand spinach was significantly more developed in plants grown at 100 mM NaCl compared to both 200 mM NaCl and control. The quinoa varieties responded differently to the increasing salt concentrations, with salt-treated "Red Head" plants significantly reducing their total root length and salt-treated "Vikinga" significantly reducing its lateral roots compared to the controls. Salt concentration near New Zealand spinach roots was lower compared to areas without roots, suggesting active salt uptake. In contrast, quinoa rhizoslides exhibited higher salt concentration in proximity to the roots, indicative of salt exclusion. The study provides insights into the adaptation and tolerance mechanisms of these two species to salinity, elucidating the mechanisms by which plants regulate their sodium uptake and root growth. The obtained results suggest that not only the selection of appropriate plant species (halophytes), but also varieties, plays a crucial role in improving crop productivity in salt-affected areas. Elucidating the salt-coping mechanisms of halophytes in relation to soil and climatic conditions is important to better predict their behavior in various saline environments. [ABSTRACT FROM AUTHOR]

Background and aims: A better understanding of plant carbon assimilation, water status and photosystem performance responses to combined heat and drought stress would help to optimize grapevine management under such limiting conditions. Methods: Gas exchange and chlorophyll fluorescence parameters were measured in potted grapevines, cv Sauvignon Blanc, before, during and after simulated six-day heat (Tmax = 40 °C) wave using heated well-watered (HW), heated drought-stressed (HD), non-heated well-watered (CW) and non-heated dry (CD) vines. Results: Photosynthesis and stomatal conductance in HW vines increased during the morning and dropped in the afternoon with respect to CW vines. Daily plant transpiration in HW almost doubled that of CW vines. When grapevines were already exposed to drought, the effects of the heat wave were negligible, with HD plants showing similar leaf photosynthesis and transpiration to their CD counterparts. Heat, but not drought stress, decreased the maximum (Fv/Fm) and effective photochemical quantum yield of PSII (φPSII), and also affected the use of absorbed energy. HW plants dissipated more radiative energy as heat, a protective mechanism of the photosystem, while HD vines increased the energy dissipated by non-regulated non-photochemical pathways, which might lead to photoinhibition damages. The different behavior could be due to the enhanced transpiration rate and consequent decrease in leaf temperature in HW as compared to HD vines. After the heat wave, only HW vines recovered the afternoon values of photosynthesis, stomatal conductance and φPSII to similar levels as those in CW vines. Conclusion: Drought had a more significant effect than heat stress on photosynthesis, stomatal conductance and transpiration. The combined heat and drought stress, however, increased the proportion of energy lost by the leaves through harmful non-regulated dissipative pathways. With adequate soil water availability, grapevines withstood the heat wave period through an increase in leaf transpiration, which decreased leaf temperature and protected the PSII from heat damage. Highlights: Drought had a stronger impact on gas exchange parameters than elevated temperature during a simulated heatwave, while heat stress was the main driver of PSII functionality and absorbed energy partitioning. Well-watered grapevines were able to recover their physiological function after a six-day heatwave (Tmax 40 °C), while plants under heat and drought stress were unable to resume PSII performance after one day of recovery. [ABSTRACT FROM AUTHOR]

The substantial depletion of freshwater reserves in many pivotal agricultural regions, attributable to the dual pressures of global climate change and the excessive extraction of water resources, has sparked considerable apprehension regarding the sustainability of future food and water security. Drip irrigation, as an efficient and precise irrigation method, reduces water loss caused by deep percolation, soil evaporation, and runoff by controlling the irrigation dosage and frequency, thus improving the efficiency of water resource utilization. Studies have shown that compared with traditional irrigation methods, drip irrigation can significantly decrease water consumption, optimize the water–energy relationship by reducing soil evaporation, increase the leaf area index, and promote crop growth, thereby enhancing plant transpiration. Although more wet and dry soil cycles from drip irrigation may increase soil CO2 emissions, it also enhances crop photosynthesis and improves crop net ecosystem productivity (NEP) by creating more favorable soil moisture conditions, indicating greater carbon sequestration potential. The advantages of drip irrigation, such as a short irrigation cycle, moderate soil moisture, and obvious dry and wet interfaces, can improve a crop's leaf area index and biomass accumulation, improve root dynamics, promote the distribution of photosynthetic products to the aboveground parts, and thus enhance crop yields. This study highlights the potential for the application of drip irrigation in arid regions where resource optimization is sought, providing strong technical support for the achievement of sustainable agricultural development. Future research needs to consider specific agricultural practices, soil types, and environmental conditions to further optimize the implementation and effectiveness of drip irrigation. [ABSTRACT FROM AUTHOR]

Evapotranspiration (ET) plays a critical role in water and energy budgets at regional to global scales. ET is composed of direct evaporation (E) and plant transpiration (T) where the latter is regulated via stomatal conductance (gsc), which depends on a multitude of plant physiological processes and hydrometeorological forcings. In recent years, significant advances have been made toward estimating gsc using a variety of models, ranging from relatively simple empirical models to more complex and data‐intensive plant hydraulic models. Using machine learning (ML) and eddy covariance flux tower data of 642 site years across 84 sites distributed across 10 land covers globally, here we show that structural constraints inherent in current empirical and plant hydraulic models of gsc limit their effectiveness for predicting ET. These constraints also prevent the models from fully utilizing the available hydrometeorological data at eddy covariance sites. Even if these gsc models are calibrated locally, structural simplifications inherent in them limit their capability to accurately capture gsc dynamics. In contrast, a ML approach, wherein the model structure is learned from the data, outperforms traditional models, thus highlighting that there still is significant room for improvement in the structure of traditional models for predicting ET. These results underscore the need to prioritize improvements in gsc models for more accurate ET estimation. This, in turn, will help reduce uncertainties in the assessments of plants' role in regulating the Earth's climate. Key Points: Current stomatal conductance models underutilize the site‐specific hydrometeorological dataStructural constraints in empirical models are more restrictive compared to plant hydraulic modelsEnhancements are needed for the simplified depiction of the water potential gradient across the root‐xylem‐leaf continuum in plant hydraulic models [ABSTRACT FROM AUTHOR]

Across diverse biomes and climate types, plants use water stored in bedrock to sustain plant transpiration. Bedrock water storage (Sbedrock), in addition to soil moisture, thus plays an important role in water cycling and should be accounted for in the context of surface energy balances and streamflow generation. Yet, the extent to which bedrock water storage impacts hydrologic partitioning and influences latent heat fluxes has yet to be quantified at large scales. This is particularly important in Mediterranean climates, where the majority of precipitation is offset from energy delivery and plants must rely on water retained from the wet season to support summer growth. Here we present a simple and modified water balance approach to quantify the role of Sbedrock on controlling hydrologic and energy partitioning. Specifically, we tracked evapotranspiration in excess of precipitation and mapped soil water storage capacity (Ssoil, mm) across the western US in the context of Budyko's water partitioning framework. Our findings indicate that Sbedrock is necessary to sustain plant transpiration across forests in the Sierra Nevada—some of the most productive forests on Earth—as early as April every year, which is counter to the current conventional thought that bedrock is exclusively used late in the dry season under extremely dry conditions. We found that the proportion of water that returns to the atmosphere would decrease dramatically without access to Sbedrock. When converted to latent heat energy, the median monthly flux associated with evapotranspiration of Sbedrock can exceed 100 W/m2 during the dry season. Plain Language Summary: Plants frequently use water stored in bedrock (Sbedrock) in order to grow. However, the proportion of precipitation that returns to the atmosphere (evapotranspiration) versus to streams (runoff), and the amount of latent heat—the energy associated with evaporating water—used as a result of access to Sbedrock has not been measured. In Mediterranean climates, such as parts of the western US, the majority of energy (sunlight) is received during the dry season and plants must rely on water stored belowground during the wet season to sustain summer growth. In this study, we present two methods for calculating how much Sbedrock influences the amount of water returning to the atmosphere versus streams and what that corresponds to in terms of latent heat energy at the surface. We use gridded data to compare the amount of water entering (precipitation) and exiting (evapotranspiration) the area and use a mapped soil water storage capacity product to draw conclusions about the timing and magnitude of plant transpiration that is a result of access to bedrock water. Our findings indicate that some of the Earth's most productive forests use Sbedrock early in the growing season, consuming over 100 W/m2 of latent heat energy in the summer. Key Points: Plant use of bedrock storage impacts water partitioning in seasonally dry climatesIn many parts of the western United States, root‐zone storage deficits do not reset annuallyPlants may exhaust soil water storage and require bedrock water as early as April each year [ABSTRACT FROM AUTHOR]

Stomata in leaves regulate gas (carbon dioxide and water vapor) exchange and water transpiration between plants and the atmosphere. SLow Anion Channel 1 (SLAC1) mediates anion efflux from guard cells and plays a crucial role in controlling stomatal aperture. It serves as a central hub for multiple signaling pathways in response to environmental stimuli, with its activity regulated through phosphorylation via various plant protein kinases. However, the molecular mechanism underlying SLAC1 phosphoactivation has remained elusive. Through a combination of protein sequence analyses, AlphaFold-based modeling and electrophysiological studies, we unveiled that the highly conserved motifs on the N-and C-terminal segments of SLAC1 form a cytosolic regulatory domain (CRD) that interacts with the transmembrane domain(TMD), thereby maintaining the channel in an autoinhibited state. Mutations in these conserved motifs destabilize the CRD, releasing autoinhibition in SLAC1 and enabling its transition into an activated state. Our further studies demonstrated that SLAC1 activation undergoes an autoinhibition-release process and subsequent structural changes in the pore helices. These findings provide mechanistic insights into the activation mechanism of SLAC1 and shed light on understanding how SLAC1 controls stomatal closure in response to environmental stimuli. [ABSTRACT FROM AUTHOR]

Sugarcane is the primary renewable energy source in Brazil, necessitating efficient and sustainable production practices. This study assessed the impact of nitrogen sources and their combination of silicon as foliar application on carbon dioxide (CO2) emissions and physiological characteristics of sugarcane cultivated in tropical environment. The experiment was conducted using the second sugarcane ratoon (variety CTC-04), as 2x5 factorial design, with two sources of N-fertilizer (urea and calcium ammonium nitrate - CAN, association with DMPSA − 3,4-dimetilprirazol succínico, nitrification inhibitor) and different silicon concentrations such as 0, 150, 300, 450, and 600 g ha−1. Photosynthetic leaf gas exchange, water use efficiency, pigments, CO2 emissions (ECO2), ammonium and nitrate levels in the soil were observed. The results were subjected to analysis of variance using the F test along with polynomial regression and mean comparison tests. Using urea as a source of nitrogen, there was an increase in internal CO2 concentration of the plants by 19% in relation to treatment with calcium ammonium nitrate association with DMPSA (CAN + DMPSA). Nevertheless, urea increased ECO2 emissions into the atmosphere by up to 15.3% higher compared to CAN + DMPSA application. Foliar application of Si (300 g ha−1) reduced plant transpiration rate (21%), irrespective the source of N-fertilizer utilized. Thus, it is concluded that the use of calcium ammonium nitrate associated with a nitrification inhibitor is an interesting strategy for reducing CO2 emissions, as well as Si is capable of reducing the plant's transpiration rates, making it efficient in the use of water. [ABSTRACT FROM AUTHOR]

Photosynthesis, understood as the photosynthetic carbon assimilation rate, is one of the key processes affected by drought stress. The effects can be via decreased CO2 diffusion and biochemical constraints. However, there is still no unified consensus about the contribution of each mechanism to the drought response. This research assessed the underlying limitations to photosynthesis in nine peanut genotypes (Arachis hypogaea L.) with different water strategies (water savers vs water spenders) under progressive drought. Water saver cultivars close the stomata earlier during drought, resulting in decreased transpiration and photosynthesis, which results in less water depletion in the soil, while water spenders maintain the stomata open during drought. In order to test the performance of these genotypes, growth, transpiration per plant, gas exchange measurements, chlorophyll fluorescence and A/Ci response curves were analyzed under drought and well‐watered conditions. In general, drought first affected photosynthesis (at the leaf and canopy level) via stomatal closure and then by impacts on chlorophyll fluorescence in all genotypes, but at different intensity levels. The maximum rate of carboxylation and the maximum rate of electron transport, physiological characteristics related to biochemical constraints, were not affected during the onset of drought, but they were decreased at the end of the drought period, with the exception of the PI 493329 genotype that showed higher stomatal conductance due to a bigger root system. The findings presented here highlight the importance of genetic variation in the photosynthetic response of peanut to drought, which should be considered when breeding for future climates. [ABSTRACT FROM AUTHOR]

Modifying root systems by crop breeding has been attracting increasing attention as a potentially effective strategy to enhance the sustainability of agriculture by increasing soil organic matter (SOM) stocks and soil quality, whilst maintaining or even improving yields. We used the new soil‐crop model USSF (Uppsala model of Soil Structure and Function) to investigate the potential of this management strategy using winter wheat as a model crop. USSF combines a simple (generic) crop growth model with physics‐based descriptions of soil water flow, water uptake and transpiration by plants. It also includes a model of the interactions between soil structure dynamics and organic matter turnover that considers the effects of physical protection and microbial priming on the decomposition of SOM. The model was first calibrated against field data on soil water contents and both above‐ground and root biomass of winter wheat measured during one growing season in a clay soil in Uppsala, Sweden using the GLUE method to identify five 'acceptable' parameter sets. We created four model crops (ideotypes) by modifying root‐related parameters to mimic winter wheat phenotypes with improved root traits. Long‐term (30‐year) simulations of a conventionally tilled monoculture of winter wheat were then performed to evaluate the potential effects of cultivating these ideotypes on the soil water balance, soil organic matter stocks and grain yields. Our results showed that ideotypes with deeper root systems or root systems that are more effective for water uptake increased grain yields by 3% and SOM stocks in the soil profile by ca. 0.4%–0.5% in a 30‐year perspective (as an average of the five parameter sets). An ideotype in which below‐ground allocation of dry matter was increased at the expense of stem growth gave even larger increases in SOM stocks (ca. 1.4%). An ideotype combining all three modifications (deeper and more effective root systems and greater root production) showed even more promising results: compared with the baseline scenario, surface runoff decreased while yields were predicted to increase by ca. 7% and SOM stocks in the soil profile by ca. 2%, which is roughly equivalent to ca. 20% of the 4‐per‐mille target (https://4p1000.org/). [ABSTRACT FROM AUTHOR]

The adaption of plants to stressful environments depends on long-distance responses in plant organs, which themselves are remote from sites of perception of external stimuli. Jasmonic acid (JA) and its derivatives are known to be involved in plants' adaptation to salinity. However, to our knowledge, the transport of JAs from roots to shoots has not been studied in relation to the responses of shoots to root salt treatment. We detected a salt-induced increase in the content of JAs in the roots, xylem sap, and leaves of pea plants related to changes in transpiration. Similarities between the localization of JA and lipid transfer proteins (LTPs) around vascular tissues were detected with immunohistochemistry, while immunoblotting revealed the presence of LTPs in the xylem sap of pea plants and its increase with salinity. Furthermore, we compared the effects of exogenous MeJA and salt treatment on the accumulation of JAs in leaves and their impact on transpiration. Our results indicate that salt-induced changes in JA concentrations in roots and xylem sap are the source of accumulation of these hormones in leaves leading to associated changes in transpiration. Furthermore, they suggest the possible involvement of LTPs in the loading/unloading of JAs into/from the xylem and its xylem transport. [ABSTRACT FROM AUTHOR]

The analysis of the stable isotopic composition of hydrogen and oxygen in water samples from soils and plants can help to identify sources of vegetation water uptake. This approach requires that the heterogeneous nature of plant and soil matrices is carefully accounted for during experimental design, sample collection, water extraction and analyses. The comparability and shortcomings of the different methods for extracting water and analyzing isotopic composition have been discussed in specialized literature. Yet, despite insightful comparisons of extraction methods and benchmarking methodologies of laboratories worldwide, the community still lacks a roadmap to guide sample collection, extraction, and isotopic analyses, and many practical issues for potential users remain unresolved: for example, which (soil or plant) water pool(s) does the extracted water represent? These constitute a hurdle for the implementation of the approach by newcomers. Here, we summarize discussions led in the framework of the COST Action WATSON ("WATer isotopeS in the critical zONe: from groundwater recharge to plant transpiration"—CA19120). We provide guidelines for (1) sampling soil and plant material for isotopic analysis, (2) methods for laboratory or in situ water extraction, and (3) measurements of isotopic composition. We highlight the importance of considering the process chain as a whole, from experimental design to isotopic analysis to minimize biased estimates of the relative contribution of different water sources to plant water uptake. We conclude by acknowledging some of the limitations of this methodology and advice on the collection of key environmental parameters prior to sample collection for isotopic analyses. This article is categorized under:Science of Water > Hydrological ProcessesScience of Water > Water and Environmental ChangeScience of Water > Water Extremes [ABSTRACT FROM AUTHOR]

Strawberry plants have shallow roots and large leaves, which are highly sensitive to variations in water levels. To explore the physicochemical and molecular mechanisms of strawberry response to water stress, and provide new ideas for strawberry scientific irrigation, we measured the transpiration rate, fresh weight, biomass gain, and other indicators of potted "Zhangji" strawberry plants under drought and waterlogging treatments using a Plantarray system. Transcriptomic and metabolomic analyses of strawberry leaves following mild drought, moderate drought, severe drought, and rehydration treatments were performed to identify key genes and metabolites involved in the response to drought stress. Below a certain threshold, the transpiration rate of strawberry plants was significantly lower after the deficit irrigation treatment than the conventional water treatment. Transcriptome analysis revealed that genes involved in oxidoreductase activity and in sulfur and nitrogen metabolism were up-regulated, as well as starch and sucrose. Strawberry plants secrete various endogenous growth hormones to maintain their normal growth under drought stress. The syntheses of salicylic acid (SA) and abscisic acid (ABA) were up-regulated in the mild and moderate drought treatments. However, the syntheses of 1-aminocyclopropanecarboxylic acid (ACC) and indole-3-acetic acid (IAA) were down-regulated in severe drought treatment and up-regulated in rehydration after severe drought treatment. [ABSTRACT FROM AUTHOR]

Limited attention has been given to the persistent impacts of diverse herbicides present in soil on the growth of successive crops in agricultural production. Therefore, the objective of this experiment is to thoroughly examine atrazine residues toxic reactions in lucern (Medicago sativa L.). This experiment aims to thoroughly investigate the toxic response of atrazine in lucern. Lucern sourced from Henan Seed Company in China. The study employed the soil addition method to investigate the impacts and correlations of diverse concentrations of atrazine herbicide residues with growth indicators, photosynthetic features, chlorophyll fluorescence parameters of lucern. The results showed that with the increase of atrazine residue (0.0-2.0 mg·kg-1), the plant height (PH), root length (RL), stem dry weight (SDW) and root dry weight (RDW) decreased to 81.8%, 81.7%, 92.3% and 85.2%, respectively. SPAD value, net photosynthetic rate (Pn), stomatal conductance (GS), transpiration rate (Tr), the PSII maximum quantum yield (Fv/Fo), maximum photochemical efficiency (Fv/Fm), actual photosynthetic efficiency (Y(II)), PSII coefficient of photochemical fluorescence quenching (qP) and photosynthetic electron transport rate (ETR) decrease by 62.1%, 83.4%, 84.1%, 95.7%, 76.8%, 11.8%, 84.5%, 46.1% and 63.1%, respectively. However, the intercellular carbon dioxide concentration (Ci) and non-photochemical quenching coefficient (NPQ) increased by 46.2% and 37.5%, respectively. Ci was positively correlated with Fv/Fo, Fv/Fm, qP, Y(II) and ETR (P<0.01), SPAD, Pn and Gs were significantly negatively correlated with Tr (P<0.01), were significantly positively correlated with Tr, Fv/Fo, Fv/Fm, qP, Y(II) and ETR (P<0.01). The potential toxicity risk of atrazine residues to plants was assessed by photosynthetic characteristics and chlorophyll fluorescence parameters. Although herbicide application is essential for food production, appropriate concentration management methods must be adopted to ensure the sustainable development of agricultural ecology. [ABSTRACT FROM AUTHOR]

Evapotranspiration (ET) partitioning distinguishes the soil evaporation (E) and plant transpiration (T) components and is crucial for understanding the land‐atmosphere interactions and ecosystem water budget. However, the mechanism and controls of ET partitioning for subtropical forests in heterogeneous environments remain poorly understood. Here, we present δ18O and δ2H of about 1,527 isotope samples including atmospheric water, soil and plant water during different seasons in 2 years of 2020–2021 from a coniferous forest across Southeast China. We used the isotopic mass balance of ecosystem water pools, the Craig‐Gordon model and the Keeling‐Plot method to partition T from ET (T/ET) and quantify the controls on T/ET. Results indicated that the uncertainty in the T/ET was principally from the soil water evaporation (δE) value, about 20–30 cm was found to be a reasonable evaporating front depth for estimating δE in this coniferous forest. T/ET presented a "U" shape diurnal pattern and varied from 66.7% to 89.9%. Isotope‐based T/ET in autumn with high temperatures and little rain was higher than those in the summer and winter seasons. Relative humidity (or vapour pressure deficit) dominated the diurnal T/ET variations (relative contributions of > 40%) in summer and autumn, while air temperature and soil water content were the main controls in winter. Our study also showed that δ18O‐derived T/ET was consistent with that of δ2H, although δ2H was found to be more stable in ET partitioning, the dual stable isotope approach should be employed in future studies for the uncertainties brought by samplings or measurements. The agreement between the isotope‐based T/ET and ET partitioning approach that uses eddy covariance and sap flux data was stronger at midday. These isotope‐inferred ET partitioning can inform land surface models and provide more insights into water management in subtropical forests. [ABSTRACT FROM AUTHOR]

Land management can moderate or intensify the impacts of a warming atmosphere. Since the early 1980s, nearly 116,000 km2 of cropland that was once held in fallow during the summer is now planted in the northern North American Great Plains. To simulate the impacts of this substantial land cover change on regional climate processes, convection‐permitting model experiments using the Weather Research and Forecasting model were performed to simulate modern and historical amounts of summer fallow. The control simulation was extensively validated using multiple observational data products as well as eddy covariance tower observations. Results of these simulations show that the transition from summer fallow to modern land cover led to ∼1.5°C cooler temperatures and decreased vapor pressure deficit by ∼0.15 kPa during the growing season across the study region, which is consistent with observed cooling trends. The cooler and wetter land surface with vegetation led to a shallower planetary boundary layer and lower lifted condensation level, creating conditions more conducive to convective cloud formation and precipitation. Our model simulations however show little widespread evidence of land surface changes effects on precipitation. The observed precipitation increase in this region is more likely related to increased moisture transport by way of the Great Plains Low Level Jet as revealed by the ERA5 reanalysis. Our results demonstrate that land cover change is consistent with observed regional cooling in the northern North American Great Plains but changes in precipitation cannot be explained by land management alone. Plain Language Summary: The northern part of the North American Great Plains have seen a globally‐unique early season climate cooling over the past five decades, with a corresponding increase in precipitation. This cooling and moistening trend has coincided with a large‐scale decrease in the practice of leaving fields bare ("fallow") during the growing season that was recommended in the early twentieth century to help conserve water for subsequent crops. Fallow fields can become quite hot in the absence of cooling from plant transpiration, and add less moisture to the atmosphere that can help contribute to rainfall. Cooler and moister air that arises from planted fields can make precipitation more likely, but is this the cause of observed climate trends in the northern Plains? We ran the Weather Research and Forecasting Model with historical and modern expanses of fallow on the land surface. Model results are consistent with observed early growing season climate cooling but do not predict substantial changes in precipitation, which instead are more consistent with additional moisture transport from the southern border of our study region. Key Points: Early growing season cooling in the northern North American Great Plains is consistent with summer fallow reductionWeather Research and Forecasting model predictions indicate that fallow reduction does not explain increases in precipitationIncreased moisture transport from the Great Plains Low Level Jet is consistent with observed increases in precipitation [ABSTRACT FROM AUTHOR]

Accurate estimation and attribution of large‐scale changes in plant transpiration are critical to understand the impacts of vegetation dynamics on the terrestrial hydrological cycle. However, these aspects remain poorly understood due to the limited reliability of global transpiration products. Here we compile data from 101 site‐based transpiration measurements across the globe and use them to constrain three biophysically based data‐driven transpiration products. The constrained transpiration reveals a prominent increasing trend of 0.61–0.79 mm yr−2 during 1980–2021, which is overestimated by 8%–32% in unconstrained transpiration. We further find that the global transpiration increase is mainly driven by leaf area index increase (40%), followed by climate change (19%), though offset partly by CO2‐induced stomatal closure (−38%) and land use and cover change (−3%). Our refined estimates indicate a less substantial increase of global transpiration than previously thought, improving the understanding of transpiration change impact on global hydrological cycle. Plain Language Summary: As a major component of terrestrial evapotranspiration, plant transpiration plays a critical role in global hydrological cycle and climate. However, transpiration and its changes are far from constrained due to the lack of field observations. By compiling a large number of in situ transpiration measurements, we correct three widely used transpiration products using the in situ data (i.e., constraints). We find that the original transpiration trend reflects an overestimation by 8%–32% compared to our constrained results, indicating that cautions should be taken when using the unconstrained products to detect transpiration trend. By combining five land surface models, we further find that the transpiration increase is mainly driven by leaf area index increase and climate change, whereas CO2‐induced stomatal closure and land use and cover change offset a considerable part of this increase. Our results improve the understanding the transpiration changes and the underlying drivers over the past four decades. Key Points: We compile data from 101 site‐based transpiration measurements across the globe and use them to constrain three transpiration productsConstrained transpiration reveals an increasing trend of 0.61–0.79 mm yr−2, while original transpiration overestimates this trend by 8%–32%Global transpiration increase is mainly driven by LAI increase and climate change, through offset partly by stomatal closure and LUCC [ABSTRACT FROM AUTHOR]

As plant distribution and performance are determined by both environmental and genetic factors, clarifying the contribution of these two factors is a key for understanding plant adaptation and predicting their distribution under ongoing global warming. Betula ermanii is an ideal species for such research because of its wide distribution across diverse environments. Stomatal density and size are crucial traits that plants undergo changes in to adapt to different environments as these traits directly influence plant photosynthesis and transpiration. In this study, we conducted a multi‐location common garden experiment using B. ermanii to (1) clarify the contribution of both environmental and genetic factors to the variation in stomatal density and size of B. ermanii, (2) demonstrate the differences in the plasticity of stomatal density and size among B. ermanii populations, and (3) understand how stomatal density and size of B. ermanii would respond to increased temperature and changing precipitation patterns. Genetic factors played a more significant role in stomatal size than environmental factors, suggesting that B. ermanii struggles to adjust its stomatal size in response to a changing environment. Our results also revealed a positive correlation between stomatal size plasticity and original habitat suitability, indicating that in B. ermanii populations in harsh environments exhibit lower adaptability to environmental shifts. Although stomatal density and size of B. ermanii showed the significant responses to increased temperature and shifting precipitation patterns, the response ranges of stomatal density and size to the environmental factors varied among populations. Our findings highlighted the interplay between genetic and environmental factors in determining the intraspecific variation in stomatal density and size in B. ermanii. This indicated that certain populations of B. ermanii exhibit limited stomatal plasticity and adaptability, which could directly affect photosynthesis and transpiration, suggesting potential population‐specific fitness implications for B. ermanii under future climate change. [ABSTRACT FROM AUTHOR]