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Craspedia G.Forst., a genus of tribe Gnaphalieae (Compositae/Asteraceae), is confined to Australia and New Zealand. Twelve species, including Craspedia blepharia Breitw. & Courtney, which we are describing here, are now recognised in New Zealand. Craspedia blepharia is known only from Garibaldi Ridge in Nelson/Tasman, South Island of New Zealand. It is a strong calcicole, confined to exposed, vertical surfaces of limestone cliffs and dolines and quartzose sandstone cliffs which receive calcium-rich seep-water. Its rosettes grow either individually or in dense clumps on cliff faces, thus allowing the plants to receive water from surface water flow. It is distinguished from other New Zealand Craspedia by its rosette leaves clad with a hispid adaxially very dense and abaxially sparse indumentum of very long (2.2–3 mm), usually curved, uniseriate, multiseptate, usually slightly brown or colourless, translucent trichomes that may have a very thin curly, flagellate tip, and leaf margins with a thin white rim formed by the flagellate tips of these long, curved trichomes. We are providing the formal taxonomic treatment together with illustrations and descriptions of its morphology, distribution, habitat, ecology, phenology, and etymology, as well as an assessment of its conservation status. [ABSTRACT FROM AUTHOR]

Introduction: With increasing drought stress due to climate change and water scarcity, the agricultural sector has sought innovative strategies to mitigate the detrimental effects on crop productivity. One approach that has received significant attention is the use of fertilizers and biostimulants as potential means of alleviating drought stress. Methods: In this study, five different irrigation levels including 100% (control), 80% (slight stress), 60% (mild stress), 40% (moderate stress), and 20% (severe stress) of field capacity (FC) and seaweed extract (SWE) at three concentrations (0, 5, and 10 g/L) were applied to the pots containing one-year-old licorice (Glycyrrhiza glabra L.) plants in a factorial completely randomized design experiment with three replications for eight weeks. Results and discussion: The glycyrrhizic acid content increased with water stress intensity without the application of SWE until severe (20% FC) water stress treatment. The application of 10 g/L SWE under 100% FC led to a significant increase in the glycyrrhizic acid value (32.5±0.889 mg/g DW) compared with non-SWE application (30.0±1.040 mg/g DW). The maximum glabridin content (0.270±0.010 mg/g DW) was obtained under irrigation of 20% field capacity with 10 g/L SWE application. In addition, the activity of the all studied enzymes such as APX (ascorbate peroxidase), CAT (catalase), POD (peroxidase), and SOD (superoxide dismutase) were boosted by increasing the water stress levels. The use of SWE further enhanced the increase of some of these metabolites and enzymes, which, in turn, helped the plant to tolerate stress conditions through the scavenging of more ROS (Reactive oxygen species), wherein for this purpose, the SWE 10 g/L was more effective than other concentration. The plants efficiently eliminated ROS driven from drought stress by both non-enzymatic and enzymatic systems. [ABSTRACT FROM AUTHOR]

Summary: Plant response to water stress involves multiple timescales. In the short term, stomatal adjustments optimize some fitness function commonly related to carbon uptake, while in the long term, traits including xylem resilience are adjusted. These optimizations are usually considered independently, the former involving stomatal aperture and the latter carbon allocation. However, short‐ and long‐term adjustments are interdependent, as 'optimal' in the short term depends on traits set in the longer term.An economics framework is used to optimize long‐term traits that impact short‐term stomatal behavior. Two traits analyzed here are the resilience of xylem and the resilience of nonstomatal limitations (NSLs) to photosynthesis at low‐water potentials.Results show that optimality requires xylem resilience to increase with climatic aridity. Results also suggest that the point at which xylem reach 50% conductance and the point at which NSLs reach 50% capacity are constrained to approximately a 2 : 1 linear ratio; however, this awaits further experimental verification.The model demonstrates how trait coordination arises mathematically, and it can be extended to many other traits that cross timescales. With further verification, these results could be used in plant modelling when information on plant traits is limited. [ABSTRACT FROM AUTHOR]

Water stress in the Amazon is exacerbated by rising temperatures and reduced moisture levels. However, understanding forest responses to increased aridity is hindered by limited in situ water potential observations in the Amazon. Remote sensing of water content has emerged as a promising metric. Vegetation Water Content (VWC) diurnal dynamics is hypothesized to reflect water stress responses. Conventional sensors' low sampling rates impede capturing and studying sub‐daily VWC dynamics. Leveraging Global Navigation Satellite System Reflectometry (GNSS‐R) with unprecedented sampling rates, this study reveals significant disparities in morning and evening VWCs in the Amazon, for example, by ≈ ${\approx} $1.1 and 1.0 kg/m2 ${\mathrm{m}}^{2}$ during the wet and dry seasons of 2019. A strong correlation (R=0.8) $(R=0.8)$ between Δ ${\Delta }$VWC (the difference between evening and morning VWCs) and vapor pressure deficit is observed in Amazonian peatland. This highlights the potential of VWC from innovative remote sensing techniques in elucidating water stress dynamics in critical ecosystems. Plain Language Summary: In the Amazon rainforest, rising temperatures and decreasing moisture levels are causing plants to experience more water stress. However, scientists have struggled to understand how the forests are responding to these drier conditions as direct measurements of plant moisture content do not provide sufficient coverage. Recently, researchers have started using satellites to measure water in plants, which could help us understand how they are coping with the lack of water. However, conventional sensors hardly offer measurements often enough to capture the daily changes in plant water levels. This study uses a novel satellite observation technique, Global Navigation Satellite System Reflectometry, that offers measurements with unprecedented frequency. It is found that there are significant differences in plants' water content in the morning compared to the evening in the Amazon, for example, by ≈ ${\approx} $1.1 and 1.0 kg/m2 ${\mathrm{m}}^{2}$ during the wet and dry seasons of 2019. This study reveals that the difference level responds significantly to environmental aridity. As a result, novel satellite methods could help us better understand how water stress is affecting the Amazon rainforest. Key Points: Global Navigation Satellite System Refractometry offers unprecedented sampling, unveiling Amazon's diurnal vegetation water contentVegetation water content generally peaks in mornings, fluctuating significantly throughout the dayAmazonian peatland's VWC diurnal cycle correlates strongly (R=0.8) $(R=0.8)$ with vapor pressure deficit, proposed as a water stress indicator [ABSTRACT FROM AUTHOR]

The current study was conducted to mitigate salt stress on Calendula officinalis L. plants using Streptomyces (Sm) bacteria alone or in combination with potassium nanoparticles (K NPs). Based on the results, morphometric characters, leaf SPAD and relative water content in plants treated with Sm bacteria and K NPs increased compared to the nontreated control under salinity stress. However, leaf ionic leakage, malondialdehyde (MDA) and hydrogen peroxide (H2O2) content decreased considerably in these treated plants. Also, under salt stress, the activity of antioxidant enzymes was higher in Sm bacteria + K NPs -treated plants than in controls. In all plants, endogenous indole acetic acid (IAA) content increased compared to plants grown in non-saline conditions. Inoculated plants reflected a relative increase in IAA by about 28% over the uninoculated plants. The highest amount of abscisic acid (ABA) and putrescine (Put) was related to those plants treated with Sm bacteria + K NPs, which the amounts were 43% and 47% higher than in control plants, respectively. Application of Sm bacteria + K NPs had a helpful outcome on both macronutrients (N-NO-3, P, K and Mg) and micronutrients (Fe, Zn, and Mn) of vines leaves. In general, the inoculation of Sm bacteria + K NPs application by improving the uptake of nutrients, regulating phytohormones and increasing the antioxidant enzymes activity resulted in salinity tolerance improvement in calendula plants. [ABSTRACT FROM AUTHOR]

Water stress is one of the most significant abiotic stresses that disrupts the osmotic balance of plants and consequently reduces their growth and performance. In recent years, it has been found that serotonin, as a signaling and regulatory molecule, can play important roles in the growth and development of plants and enhance their tolerance to abiotic stresses. Saffron is a plant known for its medicinal and culinary properties. Its distinct flavor, aroma, and vibrant color make it a sought-after ingredient in various cuisines and traditional medicines. The aim of this study is to investigate the possible effect of serotonin growth regulator on some morphophysiological and biochemical characteristics of saffron plant under water stress conditions. Water stress was applied using polyethylene glycol 6000 at a level of 30%, w/v. Serotonin was also applied exogenously at a concentration of 100 µM in both foliar and root applications. The experimental findings demonstrated that water stress had a detrimental impact on various growth and photosynthetic parameters including FW, DW, SH, RWC, photosynthetic pigments content, Pn, Fv/Fm, C and Ci. Under these conditions, H2O2 content and ion leakage increased. The increase in the content of proline and sugars also confirmed that the saffron plant was placed in unfavorable growth conditions. Serotonin application in both foliar and root applications and especially root treatment under stressful conditions improved plant growth by activating enzymatic and non-enzymatic antioxidant systems. Overall, the exogenous application of serotonin increased the resistance of saffron plants to water stress. [ABSTRACT FROM AUTHOR]

This study identifies the relationships between the δ13C and δ18O signatures of extant charophyte carbonates (δ13CCARB and δ18OCARB) and the δ13C of dissolved inorganic carbon and δ18O of water (δ13CDIC and δ18OWATER), respectively, and the structure of charophyte beds and the physico‐chemical properties of the ambient water. Inter‐ and intra‐specific differences and lake‐related variability are assessed.Four morphologically different charophyte species (Nitellopsis obtusa, Chara tomentosa, Chara rudis, Chara contraria) were studied in four charophyte‐dominated lakes (Chara‐lakes) in Central Europe. A wide distribution of the species in calcium‐rich freshwater lakes, where they form extensive underwater beds and contribute to the deposition of calcareous sediments, makes the study representative of Chara‐lakes. Charophytes and water above them were sampled monthly (June–September 2008) at permanent study sites. Additionally, three comparative macrophyte‐free pelagic sites were sampled in each lake.For all the charophytes studied, there was a greater variation in the δ13C and δ18O values of the encrustations than of the ambient and pelagic waters. Except for N. obtusa and C. tomentosa, the species differed significantly in the δ13CCARB values. The encrustations were enriched in 13C compared to water DIC. Chara tomentosa encrustations were significantly depleted in 18O compared to N. obtusa and C. contraria. In contrast to Chara species, N. obtusa encrustation was 18O‐enriched compared to surrounding water. The largest isotope differences between carbonate encrustations and surrounding water were found for C. rudis.Considering the δ13CCARB versus δ13CDIC values, only slender species (i.e. N. obtusa and C. contraria) precipitated encrustations close to isotopic equilibrium with water DIC. Based on theoretical δ18OCALCULATED and measured δ18OCARB values, only C. tomentosa precipitated encrustation in equilibrium with the δ18OWATER.Using redundancy analysis, the δ13CCARB values positively correlated with the δ13CDIC and δ18OWATER values and the percent volume of water inhabited by plants. The depth of sites, water mineralisation, alkalinity and fertility were inversely correlated with the δ13CCARB. The redundancy analysis revealed a clear division of samples into species and lakes; lakes were especially distinct.We postulate that the stable C and O isotope compositions of charophyte encrustations are lake‐ rather than species‐specific and that the isotopic signatures of charophyte carbonates are representative of the entire lake epilimnion, not just the vegetated littoral zone. Furthermore, the isotopic signal of bulk sediment can provide environmental information that is as useful as species‐specific isotope values. [ABSTRACT FROM AUTHOR]

Premise: Seed germination involves risk; post‐germination conditions might not allow survival and reproduction. Variable, stressful environments favor seeds with germination that avoids risk (e.g., germination in conditions predicting success), spreads risk (e.g., dormancy), or escapes risk (e.g., rapid germination). Germination studies often investigate trait correlations with climate features linked to variation in post‐germination reproductive success. Rarely are long‐term records of population reproductive success available. Methods: Supported by demographic and climate monitoring, we analyzed germination in the California winter‐annual Clarkia xantiana subsp. xantiana. Sowing seeds of 10 populations across controlled levels of water potential and temperature, we estimated temperature‐specific base water potential for 20% germination, germination time weighted by water potential above base (hydrotime), and a dormancy index (frequency of viable, ungerminated seeds). Mixed‐effects models analyzed responses to (1) temperature, (2) discrete variation in reproductive success (presence or absence of years with zero seed production by a population), and (3) climate covariates, mean winter precipitation and coefficient of variation (CV) of spring precipitation. For six populations, records enabled analysis with a continuous metric of variable reproduction, the CV of per‐capita reproductive success. Results: Populations with more variable reproductive success had higher base water potential and dormancy. Higher base water potential and faster germination occurred at warmer experimental temperatures and in seeds of populations with wetter winters. Conclusions: Geographic variation in seed germination in this species suggests local adaptation to demographic risk and rainfall. High base water potential and dormancy may concentrate germination in years likely to allow reproduction, while spreading risk among years. [ABSTRACT FROM AUTHOR]

Background: Soil water and organic carbon (C) are key factors affecting the growth and development of apple seedlings. The objective of the study was to investigate the effects of different soil moisture and glucose supplies on apple seedling growth and soil enzyme activities. We hypothesized that the growth of apple seedlings was affected by soil water and C content through their effects on root structure, plant physiological properties and soil enzymatic activities. A pot experiment consisting of nine treatments was set up, including three water treatments with soil moisture contents at 75–85% (normal irrigation, CK), 65–75% (light water stress, LS), and 55–65% (mild water stress, MS) of the soil field capacity, in combination with three glucose treatments with carbon/nitrogen (C/N) ratio of 7.5 (C1, no adding glucose), 10 (C2) and 15 (C3), respectively. Results: Results showed that the LSC2 treatment significantly increased plant height by 7%, stem diameter by 5% and leaf area by 17%, as compared with LSC1. Also, LSC2 significantly increased root dry weight, root vitality and soil enzyme activities. Moreover, results of leaf photosynthetic, malondialdehyde (MDA), peroxidase (POD), superoxide dismutase (SOD) and proline contents also proved that adding glucose improved the drought resistance of plants. Conclusion: LSC2 treatment is more conducive to the growth of apple seedlings, and application of carbon has a good alleviation effect on plant water stress. The study demonstrated that addition of exogenous glucose alleviated light water deficiency, significantly affected root vitality, and promoted apple seedling growth. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Summary: The onset of stomatal closure reduces transpiration during drought. In seed plants, drought causes declines in plant water status which increases leaf endogenous abscisic acid (ABA) levels required for stomatal closure. There are multiple possible points of increased belowground resistance in the soil–plant atmospheric continuum that could decrease leaf water potential enough to trigger ABA production and the subsequent decreases in transpiration.We investigate the dynamic patterns of leaf ABA levels, plant hydraulic conductance and the point of failure in the soil–plant conductance in the highly embolism‐resistant species Callitris tuberculata using continuous dendrometer measurements of leaf water potential during drought.We show that decreases in transpiration and ABA biosynthesis begin before any permanent decreases in predawn water potential, collapse in soil–plant hydraulic pathway and xylem embolism spread.We find that a dynamic but recoverable increases in hydraulic resistance in the soil in close proximity to the roots is the most likely driver of declines in midday leaf water potential needed for ABA biosynthesis and the onset of decreases in transpiration. [ABSTRACT FROM AUTHOR]

In this study, a novel microwave sensing system, consisting of a microstrip self-resonant spiral coil inductively coupled to an external concentric planar probe loop, is presented and applied to the non-destructive detection of morpho-physiological plant responses to water stress. The optimised set-up of the proposed sensor ensures a highly sensitive spiral coil, which is a fundamental requirement to derive accurate information on plants' behavioural alterations related to water stress conditions. The proposed microwave sensor was tested it on two potted maize cultivars (Zea mays L.), namely " Cinquantino Bianchi " (CB) and " Scagliolo Frassine " (SF). For each cultivar, half of the samples were maintained at 100% (T100) field capacity while the other half was at 25% (T25) from 46 to 74 Days After Sowing (DAS). The frequency (f r) shift and the amplitude peaks variation of the real component of the external planar probe input impedance (ℜ(Z i n p u t )) were obtained daily by positioning the sensor on the stem. These measured data were related to morpho-physiological parameters destructively acquired at four different growth stages. The resulting linear correlation between the stem's freshwater content ( F W C s t e m ) with both f r (r > −0.64) and the amplitude peaks (ℜ (Z i n p u t )) (r > -0.70) provided evidence of the sensor's ability to identify stem dielectric properties' variations between the two water treatments. Concurrently, the sensor response demonstrated the capability to identify changes in the morphology and histology of the stem. Based on preliminary findings, the proposed sensor shows potential for employment in the real-time monitoring of plant water status, contributing to more economically and environmentally sustainable crop management practices. While the current correlations between plant water content and sensor measurements require further refinement to meet the rigorous industrial standards, nevertheless a large-scale adoption can be envisioned by leveraging IoT methodologies. • A novel sensor to non-destructively decode plant water stress responses is proposed. • Stress-induced resonance frequency and amplitude shifts in the stem signal recorded. • Stem dielectric properties were highly responsive to water content variations. • Variety-dependent adjustments of maize stem anatomy to water stress detected. • Sensor offers a valid solution for real-time monitoring of plant water needs. [ABSTRACT FROM AUTHOR]

Salinity and drought are among the most important abiotic stress factors with vital impacts on plant growth and development. Effects of different salinity and water stress levels on physiological and biochemical traits of pepper were investigated in this study. Five different salinity (S1: 0.3 dS/m; S2: 2.5 dS/m; S3: 5dS/m; S4: 7.5 dS/m; S5: 10 dS/m) and three different irrigation levels (I100: full irrigation; I75: 25% deficit; I50: 50% deficit) were used. Plant water consumption (ET) values decreased in increasing salinity levels. Pepper yield was significantly affected by both salinity and water stress. There was a 62.8% yield loss under salt stress as compared to the control treatment and a 70.1% yield loss under 50% water deficit (I50) as compared to full irrigation (I100). Irrigation water salinity and water deficits caused significant differences in physiological and photosynthetic parameters (plant height, plant fresh and dry weight, leaf area, chlorophyll, and carotenoid content). Salinity and water stress had significant impacts on enzymatic and non-enzymatic contents such as superoxide dismutase (SOD), peroxide (POD), catalase (CAT), proline, malondialdehyde (MDA), total phenolic content (TPC) and total flavonoid content (TFC). It was concluded based on present findings that irrigation waters with a salinity level up to 5 dS/m could be used in pepper cultivation, but water deficits should be avoided. [ABSTRACT FROM AUTHOR]

Soil moisture movement reveals the hydrological environment and irrigation characteristics of plants, which is very important and basic hydrological problem. A soil moisture movement algorithm based on cellular automata suitable for greenhouse was proposed to simulate the lateral flow and vertical penetration of soil water in different soil layers. Artemisia annua was used as an experimental plant, and two numerical simulations were set up to determine the minimum water replenishment and the degree of upward soil modification. To verify the performance of the model, corn was used as an experimental plant for application simulation. The numerical simulation results show that the effect of only water for plant cells is superior to soil cells, and the disturbance behavior of the underlying soil layer should be minimized during the cultivation process. The average MAE/RMSE of all soil layers is 0.86/1.06 and in deep layer (50 cm and 60 cm) is 0.53/0.64. It shows the model has a certain prediction and simulation ability, especially in deep soil layers. The proposed algorithm can simply calculate soil flow, set the minimum water replenishment, and evaluate the water replenishment efficiency, which can provide a theoretical reference for the water replenishment and soil replacement scheme. [ABSTRACT FROM AUTHOR]

Excess nutrients such as phosphate (PO43−) entering surface waters promote eutrophication, and phosphorous (P) removal is important to clear the water. Phytoremediation efforts have been used to improve water quality by varieties of P removal plants, such as water spinach (Ipomoea aquatica Forsk). Water spinach can reduce both internal and external resources of phosphorus from waterbody. The ion of lanthanum (La), one rare earth element (REE), is an immobilization substance for aqueous phosphate and also a fertilizer for plants. Therefore, lanthanum nitrate La (NO3)3 was used further to improve the phytoextraction of P from the polluted water. This study investigated the effects of La on the aqueous P removal by two genotypes of water spinach, green stem large leaves (GSLL) and green stem willow leaves (GSWL). The low concentration La (NO3)3 helped the plant to remove more phosphorous from eutrophic water, but La at high concentration lowered the removal of P. Under La (NO3)3 treatments, the optimum concentration for maximum P removal in GSLL is 3 mg/L, and for GSWL, it is 10 mg/L and P removal rates were enhanced to 95% and 96%, respectively. When the concentration of La (NO3)3 is 100 mg/L, the removal percentage of P was only 10% for both genotypes. The very high concentration of La will impose toxicity and even cause the death of the water spinach and produce secondary pollution; for example, under some specific circumstances, the bond between lanthanum and nitrates dissociates into lanthanum ions (La3⁺) and nitrate ions (NO₃⁻). If the concentration is high, then it accumulates in the aquatic water organisms and plants and causes toxicity in their bodies. If humans eat up these plants and fish, it causes toxic effects in humans. The La (NO3)3 positively affects different parameters of plants. La (NO3)3 increases the growth, pigments, enzyme activity, and malondialdehyde (MDA) of plants which were also discussed in this study. The biological mechanism should be responsible for the enhanced aqueous phosphorus removal by water spinach using lanthanum nitrate. [ABSTRACT FROM AUTHOR]

The complex relationships within desert ecosystems and their environmental conditions are reflected in patterns of plant water use. Thus, understanding the sources of water used by plants in these areas is crucial for effective resource management. In this study, we investigated the water use pattern of Haloxylon ammodendron in Semnan province, in the central plateau of Iran, using the stable isotope analysis. We employed a simple, homemade cryogenic vacuum distillation (CVD) system to directly extract water from soil samples and different plant components for subsequent analysis by mass spectrometer. The contribution of each possible water source to the plant xylem water was estimated using the IsoSource mixing model. The pattern of δ 18O values in the xylem water of H. ammodendron indicated its reliance on groundwater as a primary water resource during the wet season. Additionally, the correlation of sand particles with both δ2H and δ18O was found to be 0.32. Moreover, the δ 18O values of H. ammodendron xylem water were mainly similar to those of groundwater, suggesting the species' dominant use of groundwater. The findings of this study provide valuable insights for strategically planting H. ammodendron to mitigate impacts on groundwater resources and ensure long-term sustainability in arid and semi-arid regions. [ABSTRACT FROM AUTHOR]

The use of environmental-stress resilient plant growth promoting rhizobacteria (PGPR) offers an organic solution to sustainable agriculture, under rapid climate change. Our laboratory has previously reported the drought-ameliorating property of an exopolysaccharide-secreting PGPR strain, Bacillus endophyticus J13 on Arabidopsis thaliana. In this study, A. thaliana roots were inoculated with J13 under well-watered and water-stressed conditions (under controlled plant growth conditions). To understand the mechanism of drought amelioration, impact of J13 on plant ABA biosynthesis and signaling was analyzed. It was found that the ABA levels in water-stress, inoculated plants were lower than the water-stressed plants, without inoculation. Also, the expression of ABA biosynthesis genes: NCED3, AAO3 and ABA2, was downregulated in inoculated treatments under water-stress as compared to non-inoculated, water-stress treatments. J13 did not cause any modulation in the expression of ABA-dependent signaling gene SnRK2 and the ABA-independent signaling gene, DREB2A, under water-stress in Arabidopsis shoots. On treating the bacteria with EDTA (which negatively impacts biofilm levels), we observed that J13 fails to impart stress tolerance to plants under water deficit conditions. The soil moisture content in soil adhered to roots and exopolysaccharide (EPS) content was significantly higher in the plants under water-stressed, inoculated treatments than the non-inoculated plants. This study unravels the mechanism of drought amelioration by J-13 on Arabidopsis by modulating soil moisture content through EPS secretion, thereby eliminating the need for enhanced ABA biosynthesis and signaling. [ABSTRACT FROM AUTHOR]

Bagega community is an artisanal mining community with a history of Pb poisoning. The community is served by a small lake as an important source of water for cattle watering, irrigation, washing, and fishing among other uses. The concentration of Cd, Cr, and Pb in soil and plants at the bank, surface water, sediment, and fish of the lake were analysed using Agilent 4210 MP-AES machine after microwave digestion using the Advanced Microwave Digestion System model (Ethos easy). The concentrations of Pb and Cr in water from Bagega Lake were found to be above the WHO acceptable limits. This presents a health risk to humans and other animals that utilize directly or indirectly utilize the water in the lake. Catfish (Clarias anguillaris) and Tilapia (Oreochromis niloticus) had higher Pb and Cr concentrations in the gills than in the liver and h muscle (flesh). The concentrations of Cr, Cd and Pb of soils in the bank and sediment of Bagega Lake were below the WHO acceptable limits. A total of thirteen (13) plant species belonging to seven (7) families were identified to be dominant around the Bagega Lake during the time of study and they all show the potential of bioaccumulation of Cr and Pb based on their BCF. [ABSTRACT FROM AUTHOR]

Sodium (Na+) is a beneficial element for most plants and may replace potassium (K+) in osmoregulatory process to a certain extent, increasing plant water use efficiency. Thus, understanding coordinated mechanisms underlying the combined use of K+ and Na+ in tree drought tolerance is a key challenge for forestry in dealing with productivity and water limitations. A pot experiment with three ratios of K/Na (K-supplied, partial K replacement by Na, and K-deficient plants) and two water regimes, well-watered (W+) and water-stressed (W−), was conducted on saplings of two Eucalyptus species with contrasting drought sensitivities. We evaluated the point of stomatal closure (P gs90), xylem water potential at 12, 50, and 88% embolized xylem area (P 12, P 50, P 88), hydraulic safety margin, leaf gas exchange (A , E , g s, and dark respiration), pre-dawn and midday leaf water potential (ΨPD and ΨMD), long-term water use efficiency (WUEL) and total dry mass. Partial K replacement by Na increased leaf gas exchange, WUEL, and total dry mass, while P gs90, P 12, P 50, P 88, and ΨMD decreased (were more negative), compared with plants exclusively supplied with K and K-deficient plants of both species. Fertilized plants had narrower hydraulic safety margins than K-deficient plants, indicating that these Eucalyptus species adopt the functional adaptive strategy of operating close to their hydraulic limits to maximize carbon uptake while increasing the risk of hydraulic failure under drought stress. [ABSTRACT FROM AUTHOR]

Summary Observational evidence indicates that tree leaf area may acclimate in response to changes in water availability to alleviate hydraulic stress. However, the underlying mechanisms driving leaf area changes and consequences of different leaf area allocation strategies remain unknown. Here, we use a trait‐based hydraulically enabled tree model with two endmember leaf area allocation strategies, aimed at either maximizing carbon gain or moderating hydraulic stress. We examined the impacts of these strategies on future plant stress and productivity. Allocating leaf area to maximize carbon gain increased productivity with high CO2, but systematically increased hydraulic stress. Following an allocation strategy to avoid increased future hydraulic stress missed out on 26% of the potential future net primary productivity in some geographies. Both endmember leaf area allocation strategies resulted in leaf area decreases under future climate scenarios, contrary to Earth system model (ESM) predictions. Leaf area acclimation to avoid increased hydraulic stress (and potentially the risk of accelerated mortality) was possible, but led to reduced carbon gain. Accounting for plant hydraulic effects on canopy acclimation in ESMs could limit or reverse current projections of future increases in leaf area, with consequences for the carbon and water cycles, and surface energy budgets. [ABSTRACT FROM AUTHOR]

Investigations of safety issues related to the design and operation of high-pressure proton exchange membrane (PEM) water electrolysers have until now mainly focused on the electrolyser stack. The present study focuses on the risk of explosive mixture formation in the water recovery system, which is part of the balance of plant in water electrolysers. After a major electrolyser company experienced an unexpected detonation in their system, we analysed their process design as a base case: a low-pressure buffer tank where anodic and cathodic water is mixed with make-up deionised water poses a safety risk because an explosive gas mixture is likely to form there, resulting in severe accidents. Several retrofit options are explored using dynamic and steady-state simulation models: these options are then evaluated based on their effects on safety, general economics and operation of the plant, in addition to ease of retrofit. The results show that preventing the formation of explosive gas mixtures in the water recovery system is achievable in several ways, such as avoiding recycling cathodic water altogether, stripping it of hydrogen, flushing buffer tanks with nitrogen or oxygen, rearranging the balance of plant appropriately, or changing the control algorithms of the system. [Display omitted] • Common electrolyser plant designs can generate explosive mixtures in the balance of plant. • Such designs have led to unwanted accidents with potential for escalation. • The explosion threshold can be reached in less than 10 min from plant startup. • There are several retrofit options to ensure safe operation. [ABSTRACT FROM AUTHOR]

Earth system models (ESMs) have a limited capacity to represent plant functional diversity and shifts in trait distributions. Approaches to improving the representation of this complexity in ESMs include (i) optimality‐based approaches that predict trait–environment responses and (ii) explicitly modelling coexistence and community assembly. These approaches are expected to converge only when optimality‐based approaches identify competitively dominant strategies, which often differ from strategies that maximize ecosystem functioning or fitness components in monoculture. We used two models, LM3‐PPA (a vegetation demographic model designed as an ESM component) and BiomeE (a computationally efficient analog for LM3‐PPA), to explore how water limitation affects carbon allocation strategies of canopy trees. We compared competitive allocation strategies and those that maximize biomass or productivity in monoculture. We did not explicitly model coexistence or community assembly. Rather, we used model experiments to identify competitive and maximizing strategies in a two‐dimensional trait space under different precipitation and mortality scenarios. At 10 eastern US locations, we simulated historical, wet and dry climate scenarios, novel drought and three different mortality scenarios (low, medium or high sensitivity to water deficit). For each site and scenario, we identified the competitive strategy and three maximizing strategies (maximum biomass, productivity or drought‐tolerance). Root: leaf ratios tended to increase and leaf area tended to decrease with increasing water stress (increasing water limitation and its effects on mortality). However, relative to maximizing strategies, competitive strategies shifted towards greater allocation to roots and leaves with increasing water stress. Competitive overinvestments (greater allocation to roots and leaves by competitive strategies compared with maximizing strategies) were robust across different modelling contexts, including vegetation parameter sets (Acer vs. Populus), models (LM3‐PPA vs. BiomeE) and uncalibrated vsersus calibrated BiomeE versions. Synthesis: The theoretical prediction that competitive and maximizing allocation strategies differ under water limitation is confirmed for a demographic model designed as an ESM component. Optimality‐based trait predictions can simplify representing trait diversity in ESMs but do not always correspond to competitive outcomes. Explicitly modelling coexistence and community assembly in ESMs is challenging but is likely the most general approach to representing trait diversity. [ABSTRACT FROM AUTHOR]

Water is a crucial component for plant growth and survival. Accurately estimating and simulating plant water content can help us promptlymonitor the physiological status and stress response of vegetation. In this study, we constructed water loss curves for three types of conifers with morphologically different needles, then evaluated the applicability of 12 commonly used water indices, and finally explored leaf water content estimation from hyperspectral data for needles with various morphology. The results showed that the rate of water loss of Olgan larch is approximately 8 times higher than that of Chinese fir pine and 21 times that of Korean pine. The reflectance changes were most significant in the near infrared region (NIR, 780-1300 nm) and the short-wave infrared region (SWIR, 1300-2500 nm). Thewater sensitive bands for conifer needlesweremainly concentrated in the SWIR region. The water indices were suitable for estimating the water content of a single type of conifer needles. The partial least squares regression (PLSR) model is effective for the water content estimation of all three morphologies of conifer needles, demonstrating that the hyperspectral PLSR model is a promising tool for estimating needles water content. [ABSTRACT FROM AUTHOR]

AbstractWater deficit stress (WDS) is one of the most significant abiotic limiting factors in cultivated crops, including cotton (Gossypium barbadense L.). With global climate change and the destruction of ecological balance, the frequency and severity of drought events are increasing in many regions around the world. Therefore, the aim of the present work was to investigate the potential of using nano zinc particles (ZnO-NPs), plant growth-promoting rhizobacteria (Azospirillum sp.), and their combination to mitigate the negative impacts of WDS on cotton var. Giza 96. Extended irrigation intervals of 30 and 45 days led to considerable decreases in plant height, chlorophyll content, relative water content (RWC), yield, and cotton fiber quality compared to the optimal irrigation interval (every 15 days). When applied individually or in combination, ZnO-NPs and Azospirillum sp. can ameliorate the negative effects of WDS on cotton growth and productivity. Overall, the use of Azospirillum sp. and ZnO-NPs, either individually or in combination, has demonstrated their potential to enhance cotton growth and yield parameters (plant height, dry weight, leaf area, chlorophyll pigment, seed index, seed yield, and lint%) under prolonged irrigation intervals during 2021 and 2022 seasons. Antioxidant enzymes activity comprising catalase (CAT), peroxidase (POD), and polyphenol oxidase (PPO) and proline content were increased under drought stress. Cotton fiber quality parameters including length, strength, and micronaire were insignificantly affected under low irrigation rate. The combination of ZnO-NPs and Azospirillum sp. provided the most effective mitigation of WDS during both experimental seasons, outperforming the effects of individual applications. [ABSTRACT FROM AUTHOR]

Betula utilis exhibits intriguing characteristics and interactions with its environment and has specific adaptations that enable it to thrive in various water conditions. Drought has a prominent role in influencing the growth and development of vegetation, while temperature serves as a crucial determinant of species distribution in high-altitude environments. The investigation was centered on the eco-physiological dimension of B. utilis in areas near the treeline. Across different seasons, sites, and years, the most negative pre-dawn twig water potentials (ΨPD) and mid-day twig water potentials (ΨMD) were − 0.81 and − 1.24 MPa, respectively. The highest seasonal change (ΔΨ) in twig water potential (Ψtwig) was in the post-monsoon season. Osmotic potential at full turgor (Ψπ100) declined by − 0.66 MPa and osmotic potential at zero turgor (Ψπ0) declined by − 1.07 MPa. The highest leaf conductance (gw) of 380.26 mmol m−2 s−1 was measured in the afternoon. During the initiation of flowering, ΨPD of the twig was − 0.72 MPa and gradually rose to − 0.17 MPa by the end of the flowering period. This study provides key insight into the Ψ dynamics, leaf conductance, and phenology of B. utilis, highlighting its adaptation to changing environmental conditions and the need for effective management strategies to ensure the resilience and conservation of this Critically Endangered species. [ABSTRACT FROM AUTHOR]

Introduction: Reduced water content in the soil triggers physiological, biochemical, and morphological damage to plants, aggravated by nutritional deficiency. One possible strategy to mitigate this damage comprises the use of silicon (Si). This study investigated whether Si can mitigate the damage caused by water deficit through nutritional mechanisms in bean plants grown under field conditions. Furthermore, it investigated whether the effectiveness of Si is influenced by water availability in the soil and the Si dose supplied. Methods: Therefore, two split-plot experiments were carried out: with and without K supply. In both experiments,the treatments comprised a 3 x 4 factorial scheme. Treatments included three water regimes: 80% (no water deficit), 60% (moderate water deficit), and 40% (severe water deficit) of the soil's water retention capacity. Moreover, they comprised four doses of Si supplied via fertigation-0 kg/ha, 4 kg/ha, 8 kg/ha, and 12 kg/ha-arranged in a randomized block design with four replications. Results and discussion: The appropriate dose of Si to be applied increased with the severity of the water deficit, with the recommended dose being 6 kg/ha, 7 kg/ha, and 8 kg/ha of Si for adequate water conditions, moderate water deficit, and severe water deficit, respectively. [ABSTRACT FROM AUTHOR]

Developing an efficient and sustainable precision irrigation strategy is crucial in contemporary agriculture. This study aimed to combine proximal and remote sensing techniques to show the benefits of using both monitoring methods, simultaneously assessing the water status and response of 'Calatina' olive under two distinct irrigation levels: full irrigation (FI), and drought stress (DS, -3 to -4 MPa). Stem water potential (Ψstem) and stomatal conductance (gs) were monitored weekly as reference indicators of plant water status. Crop water stress index (CWSI) and stomatal conductance index (Ig) were calculated through ground-based infrared thermography. Fruit gauges were used to monitor continuously fruit growth and data were converted in fruit daily weight fluctuations (ΔW) and relative growth rate (RGR). Normalized difference vegetation index (NDVI), normalized difference RedEdge index (NDRE), green normalized difference vegetation index (GNDVI), chlorophyll vegetation index (CVI), modified soil-adjusted vegetation index (MSAVI), water index (WI), normalized difference greenness index (NDGI) and green index (GI) were calculated from data collected by UAV-mounted multispectral camera. Data obtained from proximal sensing were correlated with both Ψstem and gs, while remote sensing data were correlated only with Ψstem. Regression analysis showed that both CWSI and Ig proved to be reliable indicators of Ψstem and gs. Of the two fruit growth parameters, ΔW exhibited a stronger relationship, primarily with Ψstem. Finally, NDVI, GNDVI, WI and NDRE emerged as the vegetation indices that correlated most strongly with Ψstem, achieving high R² values. Combining proximal and remote sensing indices suggested two valid approaches: a more simplified one involving the use of CWSI and either NDVI or WI, and a more comprehensive one involving CWSI and ΔW as proximal indices, along with WI as a multispectral index. Further studies on combining proximal and remote sensing data will be necessary in order to find strategic combinations of sensors and establish intervention thresholds. [ABSTRACT FROM AUTHOR]

Water deficit stress is one of the chief abiotic stresses adversely affecting plant endurance leading serious effects on plant metabolism. Depending upon strength and duration of water deficit conditions, plants adjust a series of physiological, cellular and molecular mechanisms aiming a correct stress response. Some of the responses of plants to water stress include decreased growth and development and hence decrease in fresh biomass, decreased content of chlorophyll and hence the decreased rate of photosynthesis, decrease in leaf relative water content (RWC) and increased accumulation of osmolytes like proline, sucrose, soluble carbohydrates, etc. Several enzymes involved in carbohydrate metabolism seem to play a role in the multi-layered response of plants to water deficiency. Glycolysis is a central metabolic pathway that provide elasticity when production of energy for existence is confronted and is modulated to establish a novel homeostasis under stress conditions in plants. Evidence for the participation of glycolytic genes, proteins and enzymes in response to stress is established by the fact that their expression is deeply affected by exposure of plant tissues to environmental stresses such as drought. Keeping in mind the importance of glycolytic pathway during stress conditions in plants, the impact of the drought stress on plant glycolysis is the subject of current review. In addition, plant physiology and carbohydrate metabolism under drought stress are also discussed. [ABSTRACT FROM AUTHOR]

This study aims to determine the effect of the combination of POC concentration, rice washing water and planting distance on the growth and yield of mung bean plants (Vigna radiata L.) of the Vima 1 cultivar. The research was carried out in the Kedung Dadap block, Serang Village, Palimanan District, Cirebon Regency from May 2024 to August 2024. The experimental method used was using an experimental method with a group random design (RAK), consisting of 9 treatment combinations that were repeated 3 times. Data analysis was carried out using various fingerprints and further tests with the Duncan Brganda Distance Test at the level of 5%. The results showed that there was a real influence between the POC concentration of rice washing water and planting distance on the variables of plant height, number of leaves, flowering age, total number of pods, weight of dry seeds per plant, and weight of dry seeds per plot. The POC concentration of 50 ml/l rice washing water with a planting distance of 20 cm x 30 cm had the best effect on the weight of dry seeds per plot which resulted in a production of 1.65 kg/plot or equivalent to 1.83 tons/ha. [ABSTRACT FROM AUTHOR]

Chilli (Capsicum annuum) is an important spice crop in Bangladesh. This crop is very sensitive to waterlogging. Floating agriculture is an innovative system led by the local people of the southern region of Bangladesh, in which seedlings of vegetables are produced in low-lying areas using different aquatic macrophytes. An experiment was carried out to evaluate the viability of chilli cultivation in waterlogged areas, based on physiological and biochemical responses using floating agriculture. Eight different chilli varieties were subjected to floating agriculture in two different agronomic seasons. A soil-based chilli cultivation system was also trialled, to compare the utility of this method. To evaluate the performance of chilli in floating beds, plant water status, photosynthetic parameters, and leaf tissue concentrations of Na+, K+, NO3− and PO43−, chlorophyll, ascorbic acid and proline were assessed. This study shows that macrophytes utilised in floating beds provide favourable conditions for chilli cultivation under waterlogged conditions. Among the different varieties, Sakata 653 in summer and Jhilik in winter responded better than others. As the performance of chilli in the floating agriculture system was satisfactory in comparison with soil-based cultivation, floating agriculture can be an alternative agronomic method for chilli cultivation in waterlogged areas of Bangladesh. Floating agriculture is a promising way of crop cultivation under submergence. Production of chilli (Capsicum annuum), an important spice crop, is greatly affected by waterlogging. In submerged conditions, floating agriculture serves an alternative agronomic means of chilli cultivation. [ABSTRACT FROM AUTHOR]

Gas exchange measurements enable mechanistic insights into the processes that underpin carbon and water fluxes in plant leaves which in turn inform understanding of related processes at a range of scales from individual cells to entire ecosytems. Given the importance of photosynthesis for the global climate discussion it is important to (a) foster a basic understanding of the fundamental principles underpinning the experimental methods used by the broad community, and (b) ensure best practice and correct data interpretation within the research community. In this review, we outline the biochemical and biophysical parameters of photosynthesis that can be investigated with gas exchange measurements and we provide step‐by‐step guidance on how to reliably measure them. We advise on best practices for using gas exchange equipment and highlight potential pitfalls in experimental design and data interpretation. The Supporting Information contains exemplary data sets, experimental protocols and data‐modelling routines. This review is a community effort to equip both the experimental researcher and the data modeller with a solid understanding of the theoretical basis of gas‐exchange measurements, the rationale behind different experimental protocols and the approaches to data interpretation. Summary statement: This review outlines the fundamental principles underpinning photosynthetic gas exchange and gives guidance on best practice for obtaining and correctly interpreting measurements. It is meant to provide a solid foundation in gas exchange techniques to the novice and act as a point of reference for the experienced researcher. [ABSTRACT FROM AUTHOR]

As the global climate continues to change, plants will increasingly experience abiotic stress(es). Stomata on leaf surfaces are the gatekeepers to plant interiors, regulating gaseous exchanges that are crucial for both photosynthesis and outward water release. To optimise future crop productivity, accurate modelling of how stomata govern plant–environment interactions will be crucial. Here, we synergise optical and thermal imaging data to improve modelled transpiration estimates during water and/or nutrient stress (where leaf N is reduced). By utilising hyperspectral data and partial least squares regression analysis of six plant traits and fluxes in wheat (Triticum aestivum), we develop a new spectral vegetation index; the Combined Nitrogen and Drought Index (CNDI), which can be used to detect both water stress and/or nitrogen deficiency. Upon full stomatal closure during drought, CNDI shows a strong relationship with leaf water content (r2 = 0.70), with confounding changes in leaf biochemistry. By incorporating CNDI transformed with a sigmoid function into thermal‐based transpiration modelling, we have increased the accuracy of modelling water fluxes during abiotic stress. These findings demonstrate the potential of using combined optical and thermal remote sensing‐based modelling approaches to dynamically model water fluxes to improve both agricultural water usage and yields. Summary statement: Using both trait and flux measurements, we have designed a new vegetation index: the combined nitrogen and drought index. This index describes changes in leaf optical properties during nitrogen and or drought stress that can be used to improve transpiration modelling during abiotic stress. [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]

In the presented study, an efficient and fast analytical method was developed for the determination of parathion ethyl as sarin simulant by gas chromatography–mass spectrometry (GC–MS). Dispersive solid phase extraction (DSPE) was performed to concentrate parathion ethyl from soil, plant and water samples. Reduced graphene oxide–iron (II, III) oxide (rGO-Fe3O4) nanocomposite was used as an adsorbent to collect the target analyte from the aqueous sample solutions. After the optimization of extraction/preconcentration parameters, optimum conditions for adsorbent amount, eluent type, mixing type/period, eluent volume and initial sample volume were determined as 15 mg, acetonitrile, vortex/30 s, 100 µL and 10 mL, respectively. Under the optimum conditions, analytical performance of the developed DSPE-GC–MS method was evaluated in terms of limit of detection (LOD), limit of quantitation (LOQ) and dynamic range. Dynamic range, LOD and LOQ values were figured out to be 0.94–235.15 µg/kg, 0.41 µg/kg and 1.36 µg/kg (mass based), respectively. Satisfactory percent recovery results (90.3–125% for soil, 93.5–108.7% for plant, 88.5–112.9% for tap water) were achieved for soil, plant and tap water samples which proved the accuracy and applicability of the developed method. It is predicted that the DSPE-GC–MS method can be accurately used for the detection of sarin in soil, plant and water samples taken from war territories. [ABSTRACT FROM AUTHOR]

The purpose of the study is to optimize the trophic and hormonal determination of raspberry reproduction in vitro and post-aseptic adaptation ex vitro. The research was carried out on the remontant raspberry variety Delniwa of Polish selection. Laboratory studies were carried out in the conditions of the Tevitta TM laboratory (Ltd "Agrofirm Blagodatne," Cherkasy region), and experiments were laid in four stages: introduction into aseptic culture, multiplication, induction of rhizogenesis, and post-aseptic adaptation, including photoautotrophic grafting. A medium for obtaining an aseptic culture and a media for multiplication have been selected. The rate of regeneration of explants of different origins, and the percentage of regenerants from them, was compared. The dynamics of the influence of cytokinin concentrations during long-term reproduction in vitro were revealed. Cultivation on a medium with a high content of benzylaminopurine and kinetin showed the effect of accumulation of phytotoxicity. The expediency of growing graft donors for grafting at low kinetin concentrations to improve the induction of rhizogenesis is substantiated. Regenerants from media with a predominance of auxins over cytokinins had a higher regeneration potential. According to indicators of suitability for survival, perlite substrates prevailed over peat ones; however, regenerants of a smaller height were formed on them. The symptoms and harmful effects of excessive watering on plants have been established. A biomethod of insect control using insectivorous plants of the genus Drosera has been developed. The rate of rhizogenesis in bioreactor conditions with humidified and carbon dioxide-enriched air significantly exceeded root formation in conventional moist chambers. The duration of growing an adapted and well-rooted seedling in a bioreactor was 21 days, compared to 30 or more days in the control version of the experiment. The plants did not lose turgor when planted in closed soil. Adapted regenerants are successfully used as a planting material and can be used in photoautotrophic microclonal propagation as donors of cuttings. Under such conditions, the regeneration efficiency is maintained for five cutting generations. [ABSTRACT FROM AUTHOR]

Hydraulic redistribution (HR) is a common phenomenon in water‐limited ecosystems; however, it remains unclear how the volume of water transported via HR compares to other components of the hydrologic budget and how HR influences water availability for understory plant communities. In this study, we investigate the absolute and relative magnitude of HR on a forest water budget and identify potential impacts of this water subsidy to understory plant communities. We scaled tree‐level estimates of transpiration and HR of three common tree species naturally occurring in a longleaf pine woodland with plot‐level measurements of basal area to determine their magnitude at the stand scale. We trenched plots containing understory vegetation but devoid of mature trees and their connected roots to exclude HR subsidies to understory plant species. We analysed soil water isotopes and assessed leaf water potential (ΨL) in trenched and control plots to determine if HR results in mixing of water among soil strata and improves understory plant moisture status. Water inputs from HR were equivalent to >30% of total rainfall for the site during the observation period and ~40% of total tree water uptake, depending on species. A stable isotope mixing model confirmed that soil water within HR‐exposed plots was more similar to groundwater, whereas soil water within trenched plots was more similar to precipitation. Exclusion of HR via trenching decreased soil moisture and pre‐dawn ΨL for all understory species. These three lines of evidence suggest that HR from overstory trees redistributes a sizable portion of water from deeper to shallower soil profiles and that this water subsidy enhances understory plant water status. [ABSTRACT FROM AUTHOR]

Water deficit (drought) is an important environmental factor affecting physiological processes in plants. The present work focuses on the study of changes in physiological responses of juvenile plants (plants in the vegetative phase of growth BBCH 14-16) of selected sorghum genotypes Dokok, 30485, Barnard Red and Ruzrok to water deficit and after rehydration. Water deficit affected the observed physiological parameters-gas exchange and chlorophyll fluorescence. Genotypic differences were also confirmed, with Dokok appearing to be the more sensitive genotype and Ruzrok and Barnard Red appearing to be tolerant. Following rehydration, these parameters increased but did not reach the levels of the control plants. A significant decrease in photosynthetic rate (Pn), transpiration (E) and fluorescence compared to the control was found in the water-deficient variant twice for 10 days and 6 days between rehydration periods. Only in the variant where water deficit (14 days) was followed by irrigation (10 days) transpiration increased in genotype 30485. Chlorophyll fluorescence (Fv /Fm) also decreased significantly in this cultivar. The results suggest that a rehydration period of 14 days is insufficient to restore the photosynthetic functions of stressed sorghum plants. [ABSTRACT FROM AUTHOR]

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The current research examined the potential of P. stratiotes to accumulate inorganic and organic nutrients from contaminated watercourses in Egypt. It also aimed to determine whether the biomass of the plant can be safely used as animal feed. Plant and water samples were taken seasonally for a year at three different sites using three randomly assigned quadrats. There were significant seasonal differences in water pH, dissolved oxygen, transparency, and water temperature. The highest biomass (314.52 g DM/m2) was recorded during spring, while the lowest (35.38 g DM/m2) during winter. Winter contributed to the highest contents of N and P (4.09 and 0.62%), while summer had the highest Ca (2.46%), and spring had the highest of Mg and Na (1.23 and 2.65%). The highest Co, Fe, Ni, and Pb values (17.28, 2517.36, 18.99, and 48.57 mg/kg) were highest in summer. The highest levels of crude protein and carbohydrates (26.47 and 42.59%), and the greatest levels of digestible crude protein, digestible energy, metabolized energy, net energy, and gross energy (21.07%, 2.79 Mcal/kg, 2.29 Mcal/kg, 1.14 Mcal/kg and 405.97 Kcal/100 g) were recorded in winter. Summer is ideal for harvesting P. stratiotes for phytoremediation, while winter is suitable for animal feeding. [ABSTRACT FROM AUTHOR]

The two most important abiotic plant stressors that impact plant development and crop yields are water stress and salinity stress. These issues are particularly important in arid and semi‐arid regions. According to a 2019 research paper, “thirty crop species provide 90% of our food, most of which display severe yield losses under moderate salinity.” Moderate salinity is defined as extracted pore‐water salinity in the range of 4–8 dS m−1. Currently, commercially available soil moisture and bulk soil electrical conductivity sensors can estimate in situ soil pore‐water electrical conductivity with suitably calibrated soil moisture and electrical conductivity models for a wide range of soil types and growing media. With knowledge of the pore‐water electrical conductivity it is possible to estimate osmotic tension. Furthermore, there are commercially available dielectric tensiometers that provide soil water tension measurements from the water content of a porous matrix component that is in equilibrium with the water capillary forces in the surrounding soil or growing media. Combining soil moisture and soil water tension measurements enables water retention curves and the hydraulic properties of a soil to be determined. However, the overall ability of a plant to extract water from a soil or substrate is typically dominated by water tension and osmotic tension. Currently, while the technology blocks exist in different commercial offerings, the combination of a water tension and osmotic tension in an integrated sensor does not exist. A key benefit of the porous matrix in a dielectric tensiometer is that electrical measurements include a component of extracted water from the soil or growing media. With the appropriate dielectric characterization of the porous matrix, there should be no need for soil‐specific calibrations. The aim of the paper is to outline the measurement processing that could be implemented into an integrated water tension and osmotic tension sensor. [ABSTRACT FROM AUTHOR]

Drought and subsequent rewatering are common in agriculture, where recovery from mild droughts is easier than from severe ones. The specific drought threshold and factors limiting recovery are under‐researched. This study subjected maize plants to varying drought degrees before rewatering, and measuring plant water status, gas exchange, hydraulic conductance, hormone levels, and cellular damage throughout. We discovered that stomatal reopening in plants was inhibited with leaf water potentials below about −1.7 MPa, hindering postdrought photosynthetic recovery. Neither hydraulic loss nor abscisic acid (ABA) content was the factor inhibited stomatal reopening on the second day following moderate drought stress and rewatering. But stomatal reopening was significantly correlated to the interaction between hydraulic signals and ABA content under severe drought. Extended drought led to leaf death at about −2.8 MPa or 57% relative water content, influenced by reduced rehydration capacity, not hydraulic failure. The lethal threshold remained relatively constant across leaf stages, but the recoverable safety margin (RSM), that is, the water potential difference between stomatal closure and recovery capacity loss, significantly decreased with leaf aging due to delayed stomatal closure during drought. Our findings indicate hydraulic failure alone does not cause maize leaf death, highlighting the importance of RSM in future research. [ABSTRACT FROM AUTHOR]

For the effective operation of a Power-to-Hydrogen (P2H) system that integrates renewable energy sources with an Alkaline Water Electrolyzer (AWE), precise modeling of the AWE plant is paramount. This research delves into the electrothermal dynamics of the AWE and constructs an advanced Power–Temperature–Hydrogen (P–T–H) coupling model of the AWE plant. The developed model intricately captures the pivotal role of temperature in modulating hydrogen production rates, power constraints, and system flexibility. Furthermore, to enable the application of the model to system-level optimization, we undertake a rational simplification process to transform it into a linear model. Building upon this model, we devise an optimized power scheduling strategy for the P2H system that enhances the system's economic efficiency and adaptability. A comprehensive sensitivity analysis of crucial variables such as hydrogen demand, transmission line capacity, and AWE capacity underscores the strategic insights this model offers for system development and implementation. In a word, the developed P–T–H model is well feasible for the improvement of the system's operation with AWE. • The decisive role of temperature in hydrogen production properties, power limit, and operational flexibility of an AWE is demonstrated. • A novel P–T–H coupling model is proposed to capture temperature-based operation characteristics of the AWE plant. • Sensitivity analysis reveals the dependency of daily optimal revenue on hydrogen demand and transmission line capacity. [ABSTRACT FROM AUTHOR]

Key message: Winter reddening of young Douglas-fir (Pseudotsuga menziesii Mirb. Franco), triggered by large thermal fluctuations in late winter, is a critical problem for European forestry. A literature review identified certain climatic conditions that are characteristic of 'reddening' years, including warm daily temperatures, high daily temperature amplitude, low relative humidity, moderate wind speeds, as well as the occurrence of freeze-thaw cycles with cold night temperatures. By describing the triggering environmental and stand factors, we propose three hypotheses for the physiological processes leading to winter reddening, namely (i) hydraulic failure due to winter drought stress, (ii) photo-oxidative stress in shade-acclimated trees, and (iii) early cold deacclimation during warm periods. i) Low soil temperature, by reducing root water uptake, combined with anticyclonic conditions, by increasing water losses, can induce hydraulic failure in the xylem. Hydraulic failure may be further accelerated by night frosts. ii) Winter reddening can occur when low temperature and high irradiance coincide, disrupting photostasis. Overwhelming of winter photo-protection may lead to photodamage and subsequent reddening. iii) Warm periods, by inducing cold deacclimation, make trees susceptible to frost damage. Finally, the three processes may interact under atypical anticyclonic conditions in late winter (e.g. cold or dry soils, warm days, high irradiance and/or freezing nights). Indeed, trees under water stress would develop a higher sensitivity to freezing night and photooxidative stress. We therefore proposed mitigation actions to avoid exposing trees to stressful conditions based on e.g. stand characteristics, understorey vegetation and planting. [ABSTRACT FROM AUTHOR]

Introduction: Soil drought during summer in Central Europe has become more frequent and severe over the last decades. European forests are suffering increasing damage, particularly Norway spruce. Douglas-fir (Pseudotsuga menziesii (Mirbel) Franco), a non-native tree species, is considered as a promising alternative to build drought-resilient forests. The main goal of this study was to investigate the intraannual radial stem growth and sap flow performance of Douglas-fir along a precipitation gradient across Germany under severe drought. Material and methods: Sap flow and stem radial changes of up to ten trees each at four sites with different precipitation regimes were measured in combination with volumetric soil water content during the growing season of 2022. Measurements of stem radial changes were used to calculate the trees' stem water deficit, a proxy for tree water status and drought stress. Results: The severe summer drought of 2022 led to an early growth cessation and a significant reduction in daily sap flow at all four sites monitored. We could identify a site-specific threshold in soil water availability ranging between 21.7 and 29.6% of relative extractable water (REW) under which stem water reserves cannot be replenished and thereby inhibiting radial growth. We could also demonstrate that at this threshold, sap flow is heavily reduced to between 43.5 and 53.3%, and for a REW below 50%, sap flow linearly decreases by 1.1-2.0% per 1% reduction in REW. This reduction tends to follow the humidity gradient, being more pronounced at the most oceanic characterized site and suggesting an adaptation to site conditions. Even though Douglas-fir is considered to be more drought stress resistant than Norway spruce, growth and sap flow are greatly reduced by severe summer drought, which became more frequent in recent years and their frequency and intensity is likely to increase. Conclusions: Our results suggest that timber production of Douglas-fir in Central Europe will decline considerably under projected climate change, and thus pointing to site specific growth constraints for a so far promising non-native tree species in Europe. [ABSTRACT FROM AUTHOR]

The development of water-saving management relies on understanding the physiological response of crops to soil drought. The coordinated regulation of hydraulics and stomatal conductance in plant water relations has steadily received attention. However, research focusing on grain crops, such as winter wheat, remains limited. In this study, three soil water supply treatments, including high (H), moderate (M), and low (L) soil water contents, were conducted with potted winter wheat. Leaf water potential (Ψleaf), leaf hydraulic conductance (Kleaf), and stomatal conductance (gs), as well as leaf biochemical parameters and stomatal traits were measured. Results showed that, compared to H, predawn leaf water potential (ΨPD) significantly reduced by 48.10% and 47.91%, midday leaf water potential (ΨMD) reduced by 40.71% and 43.20%, Kleaf reduced by 64.80% and 65.61%, and gs reduced by 21.20% and 43.41%, respectively, under M and L conditions. Although gs showed a significant difference between M and L, Ψleaf and Kleaf did not show significant differences between these treatments. The maximum carboxylation rate (Vcmax) and maximum electron transfer rate (Jmax) under L significantly decreased by 23.11% and 28.10%, stomatal density (SD) and stomatal pore area index (SPI) under L on the abaxial side increased by 59.80% and 52.30%, respectively, compared to H. The leaf water potential at 50% hydraulic conduction loss (P50) under L was not significantly reduced. The gs was positively correlated with ΨMD and Kleaf, but it was negatively correlated with abscisic acid (ABA) and SD. A threshold relationship between gs and Kleaf was observed, with rapid and linear reduction in gs occurring only when Kleaf fell below 8.70 mmol m−2 s−1 MPa−1. Our findings demonstrate that wheat leaves adapt stomatal regulation strategies from anisohydric to isohydric in response to reduced soil water content. These results enrich the theory of trade-offs between the carbon assimilation and hydraulic safety in crops and also provide a theoretical basis for water management practices based on stomatal regulation strategies under varying soil water conditions. [ABSTRACT FROM AUTHOR]

Background: Climate change induces perturbation in the global water cycle, profoundly impacting water availability for agriculture and therefore global food security. Water stress encompasses both drought (i.e. water scarcity) that causes the drying of soil and subsequent plant desiccation, and flooding, which results in excess soil water and hypoxia for plant roots. Terrestrial plants have evolved diverse mechanisms to cope with soil water stress, with the root system serving as the first line of defense. The responses of roots to water stress can involve both structural and physiological changes, and their plasticity is a vital feature of these adaptations. Genetic methodologies have been extensively employed to identify numerous genetic loci linked to water stress-responsive root traits. This knowledge is immensely important for developing crops with optimal root systems that enhance yield and guarantee food security under water stress conditions. Results: This review focused on the latest insights into modifications in the root system architecture and anatomical features of legume roots in response to drought and flooding stresses. Special attention was given to recent breakthroughs in understanding the genetic underpinnings of legume root development under water stress. The review also described various root phenotyping techniques and examples of their applications in different legume species. Finally, the prevailing challenges and prospective research avenues in this dynamic field as well as the potential for using root system architecture as a breeding target are discussed. Conclusions: This review integrated the latest knowledge of the genetic components governing the adaptability of legume roots to water stress, providing a reference for using root traits as the new crop breeding targets. [ABSTRACT FROM AUTHOR]

Plant propagules are crucial flora memory materials in restoration practice. Awakening flora memory from plant propagules (i.e. seeds, root fragments, rhizomes, corms, and tubers) in the translocated topsoil from a donor site is a rapid method for forest restoration on degraded sites globally. However, it remains unclear to what extent manageable measures, such as light reduction and watering, affect flora memory awakening. We employed a quadratic saturation D‐optimal design in a forest topsoil translocation experiment to quantify the effects of light reduction and watering on flora memory awakening. We used the cumulative number and richness of plantlets emerging from plant propagules to represent the extent of flora memory awakening. Our results show that any combinations of light reduction and watering significantly increased both the cumulative number and richness of plantlets across different life forms. Light reduction had a significantly more positive effect on flora memory awakening than watering. Different life forms exhibited different parabolic or positive linear relationships in responses to light reduction and watering. Light reduction of about 60% of the degraded site and watering of about 80% of the donor site resulted in the highest number and richness of plantlets. We concluded that light reduction and watering combinations were effective in kick‐starting the flora memory awakening in a semiarid subtropical forest after topsoil translocation. [ABSTRACT FROM AUTHOR]

The management of nitrogen (N) fertilization is of fundamental importance in hydroponics. To reduce the supply of nitrate (NO3-) in fertigation recipes for Batavia lettuce crops grown in closed hydroponics, partial replacement of nitrate by chloride (NO3-/Cl-) at different ratios but with the same equivalent sum was experimentally tested. The experiment included four nutritional treatments in the replenishment nutrient solution, particularly T1; 0.7mMCl-/19mMNO3-, T2;2mM Cl-/17.7 mM NO3-, T3; 4 mM Cl-/15.7 mM NO3- and T4; 6 mM Cl-/13.7 mM NO3-. The results showed that reducing nitrate supply combinedwith equivalent increase in chloride application gradually reduced the gap between nitrate input and nitrogen uptake concentrations, with the smallest differences occurring in T4 treatment, which reduced the nitrate concentration in the drainage by 50%. The tested treatments led to very small variations in plant water uptake, production of fresh biomass and nutritional quality, which is justified by the proper functioning of key physiological mechanisms, such as stomatal conductance, which was followed by an increased efficiency of nitrogen use up to 25% (kg fresh biomass kg-1 N supply). The steady level of C/N ratio in the plant tissue irrespective of NO3-/Cl- supply ratio points to sufficiency in photosynthetic products and adequacy in the supply of nitrogen, although leaf Cl- content increased up to 19.6 mg g-1 dry weight in the lowest NO3-/Cl- treatment. Nutrient uptake concentrations were determined as follows: 13.4 (N), 1.72 (P), 10.2 (K), 3.13 (Ca), 0.86 (Mg,mmol L-1), 27.8 (Fe), 5.63 (Mn), 5.45 (Zn) and 0.72 (Cu, mmol L-1). This study suggests that replacing 30% of NO3- supply with Cl- in fertigation recipes for hydroponic lettuce crops reduces leaf nitrate content without affecting physiological processes, growth, and quality, verifying in parallel the role of chloride as a beneficial macronutrient. Finally, a relationship between Cl- uptake and its concentration in the root zone solution was established enabling the simulation of chloride towater consumption. [ABSTRACT FROM AUTHOR]

Classic debates in community ecology focused on the complexities of considering an ecosystem as a super-organ or organism. New consideration of such perspectives could clarify mechanisms underlying the dynamics of forest carbon dioxide (CO2) uptake and water vapor loss, important for predicting and managing the future of Earth's ecosystems and climate system. Here, we provide a rubric for considering ecosystem traits as aggregated, systemic, or emergent, i.e. representing the ecosystem as an aggregate of its individuals or as a metaphorical or literal super-organ or organism. We review recent approaches to scaling-up plant water relations (hydraulics) concepts developed for organs and organisms to enable and interpret measurements at ecosystem-level. We focus on three community-scale versions of water relations traits that have potential to provide mechanistic insight into climate change responses of forest CO2 and H2O gas exchange and productivity: leaf water potential (Ψcanopy), pressure volume curves (eco-PV), and hydraulic conductance (K eco). These analyses can reveal additional ecosystem-scale parameters analogous to those typically quantified for leaves or plants (e.g. wilting point and hydraulic vulnerability) that may act as thresholds in forest responses to drought, including growth cessation, mortality, and flammability. We unite these concepts in a novel framework to predict Ψcanopy and its approaching of critical thresholds during drought, using measurements of K eco and eco-PV curves. We thus delineate how the extension of water relations concepts from organ- and organism-scales can reveal the hydraulic constraints on the interaction of vegetation and climate and provide new mechanistic understanding and prediction of forest water use and productivity. [ABSTRACT FROM AUTHOR]