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Magnetopriming has emerged as a promising seed-priming method, improving seed vigor, plant performance and productivity under both normal and stressed conditions. Various recent reports have demonstrated that improved photosynthesis can lead to higher biomass accumulation and overall crop yield. The major focus of the present review is magnetopriming-based, improved growth parameters, which ultimately favor increased photosynthetic performance. The plants originating from magnetoprimed seeds showed increased plant height, leaf area, fresh weight, thick midrib and minor veins. Similarly, chlorophyll and carotenoid contents, efficiency of PSII, quantum yield of electron transport, stomatal conductance, and activities of carbonic anhydrase (CA), Rubisco and PEP-carboxylase enzymes are enhanced with magnetopriming of the seeds. In addition, a higher fluorescence yield at the J-I-P phase in polyphasic chlorophyll a fluorescence (OJIP) transient curves was observed in plants originating from magnetoprimed seeds. Here, we have presented an overview of available studies supporting the magnetopriming-based improvement of various parameters determining the photosynthetic performance of crop plants, which consequently increases crop yield. Additionally, we suggest the need for more in-depth molecular analysis in the future to shed light upon hidden regulatory mechanisms involved in magnetopriming-based, improved photosynthetic performance.

Leaf growth and photosynthetic characteristics of sweet potato (Ipomoea batatas var. Biru Putih) grown under different light quantities were studied in a tropical greenhouse. The stem cuttings of I. batataswith adventitious roots were grown hydroponically under (1) only natural sunlight (SL); (2) SL with supplemental LED at a PPFD of 150 μmol m -2 s -1 (SL + L-LED); and (3) SL with supplemental LED at a PPFD of 300 μmol m -2 s -1 (SL + H-LED). One week after emergence, all leaves had similar area and water content. However, leaf fresh weight and dry weight were significantly higher in plants grown under SL+L-LED and SL + H-LED than under SL due to their thicker leaves reflected by the lower specific leaf area. Plants grown under SL had significantly lower concentrations of total chlorophyll (Chl) and total carotenoids (Car) but higher Chl a/b ratio than under SL + L-LED and SL + H-LED. However, all plants had similar Chl/Car ratios. Although midday F v /F m ratio was the lowest in leaves grown under SL+ H-LED followed by SL + L-LED and SL, predawn F v /F m ratios of all leaves were higher than 0.8. Increasing growth irradiance with supplemental LED resulted in higher electron transport rate and photochemical quenching but lower non-photochemical quenching compared to those of plants grown under SL. Measured under their respective growth irradiance in the greenhouse, attached leaves grown under SL + L-LED and SL+H-LED had significantly higher photosynthetic CO 2 assimilation rate and stomatal conductance than under SL. However, measuring the detached leaves at 25 °C in the laboratory, there were no significant differences in PS II and Cyt b 6 f concentrations although light- and CO 2 -statured photosynthetic O 2 evolution rates were slightly higher in leaves grown under SL+ H-LED than under SL. Impacts of supplemental LED on leaf growth and photosynthetic characteristics were discussed., (Copyright © 2020 Elsevier GmbH. All rights reserved.)

If a browse damage index indicates that a tree has been 50% browsed by herbivores, does this mean half the leaves are entirely eaten or are all the leaves half eaten? Were the affected leaves old or young? Large or small? In sunshine or shade? Understanding what effect browsing will have on the photosynthetic capacity and the plant's survival ability clearly requires a greater understanding of browsing strategy across the canopy than can be given by a single index value. We developed stochastic models of leaf production, growth and consumption using data from kamahi (Weinmannia racemosa) trees in New Zealand which have been browsed by possums (Trichosurus vulpecula), to ascertain which of six feasible browsing strategies possums are most likely to be employing. We compared the area distribution of real fallen leaves to model output in order to select the best model, and used the model to predict the age distribution of leaves on the tree and thus infer its photosynthetic capability. The most likely browsing strategy that possums employ on kamahi trees is a preference for virgin (i.e. previously unbrowsed) leaves, consistent with the idea that browsing increases the production of chemical plant defences. More generally, our results show that herbivore browsing strategy can significantly change the whole-plant photosynthetic capability of any plant and hence its ability to survive, and therefore, herbivore damage indices should be used in conjunction with more detailed information about herbivore browsing strategy.

Ethephon (2-chloroethylphosphonic acid) is frequently used for flush management in order to maximize flowering in litchi. However, the optimal dosage of ethephon, which balances between flush control effect and the detrimental effect on leaves, is unknown. This study aimed to identify the optimal ethephon dosage and test more efficient ethephon application methods, using a drone for flush control and flowering promotion in litchi. The effects of a single manual full-tree spray of 250, 500 or 1000 mg/L of ethephon in early November on the bud break rate, leaf drop rate, net photosynthetic rate, LcFT1 expression and floral induction (panicle emergence rate and panicle number) in 'Jingganghongnuo' litchi were examined in the season of 2021–2022. In the season of 2022–2023, the effects of drone application of 1000 mg/L of ethephon in early November on bud growth and floral induction were observed. The results showed that the manual ethephon treatments were effective at enforcing bud dormancy and elongating the dormancy period and that the effects were positively dependent on dosage. One manual spray of 1000 mg/L of ethephon in late autumn enabled a dormancy period of 6 weeks. The treatments advanced seasonal abscission of old leaves in winter and caused short-term suppression on photosynthesis within 2 weeks after treatment. Ethephon treatments, especially at 1000 mg/L, enhanced the expression of LcFT1 in the mature leaves and promoted floral induction reflected by earlier panicle emergence and increased panicle emergence rate and number in the terminal shoot. The floral promotion effect was also positively dosage dependent. The cumulative chilling hours below 15 °C from the date of treatment to the occurrence of a 20% panicle emergence rate were lowered in ethephon treatments. A drone spray of 1000 mg/L of ethephon solution consumed a sixth of the manual spray solution volume and was two thirds less effective in suppressing bud break compared with manual spraying. However, it achieved a significant flowering promotion effect comparable to traditional manual spraying. The results suggest that ethephon application enhanced flowering responsiveness to chilling as well as enforced bud dormancy. The application of ethephon with a drone proved to be an efficient method for flush control and flower promotion. [ABSTRACT FROM AUTHOR]

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]

Foliar development involves successive phases of cell proliferation and expansion that determine the final leaf size, and is characterized by an early burst of reactive oxygen species generated in the photosynthetic electron transport chain (PETC). Introduction of the alternative PETC acceptor flavodoxin in tobacco chloroplasts led to a reduction in leaf size associated to lower cell expansion, without affecting cell number per leaf. Proteomic analysis showed that the biogenesis of the PETC proceeded stepwise in wild-type leaves, with accumulation of light-harvesting proteins preceding that of electron transport components, which might explain the increased energy and electron transfer to oxygen and reactive oxygen species build-up at this stage. Flavodoxin expression did not affect biogenesis of the PETC but prevented hydroperoxide formation through its function as electron sink. Mature leaves from flavodoxin-expressing plants were shown to contain higher levels of transcripts encoding components of the proteasome, a key negative modulator of organ size. Proteome profiling revealed that this differential accumulation was initiated during expansion and led to increased proteasomal activity, whereas a proteasome inhibitor reverted the flavodoxin-dependent size phenotype. Cells expressing plastid-targeted flavodoxin displayed lower endoreduplication, also associated to decreased organ size. These results provide novel insights into the regulation of leaf growth by chloroplast-generated redox signals, and highlight the potential of alternative electron shuttles to investigate the link(s) between photosynthesis and plant development. [ABSTRACT FROM AUTHOR]

Phosphorus (P) deficiency is one of the main reasons limiting plant production of Brassica napus L. Exploring the dynamics of leaf intracellular substances and the correlations with photosynthesis and growth helps to understand the response mechanisms of B. napus L. to P deficiency. This study conducted experiments on B. napus L. plants by measuring the leaf electrophysiological parameters, leaf structure, elastic modulus (Em), photosynthesis, and growth indices under different P treatment conditions. The dynamics of leaf intracellular water and nutrients of B. napus L. were calculated and analyzed by using the electrophysiological parameters, and the plant tolerance threshold to low-P stress was discovered. The results indicated that the status of the leaf intracellular water and nutrients remained stable when the P concentration was not lower than 0.250 mmol·L−1, but maximized the photosynthesis and growth at a P level of 0.250 mmol·L−1. The 0.125 mmol·L−1 P concentration significantly decreased the mesophyll cell volume, and the palisade–sponge ratio and tightness degree of leaf tissue structure were remarkably increased. This led to an increase in cell elastic modulus, and significantly improved the water retention capacity of leaf cells. At the same time, the intracellular water use efficiency and total nutrient transport capacity of leaves remained stable. As a result, the photosynthesis and growth of plants were maintained at the same level as that of the control group. However, photosynthesis and growth were clearly inhibited with a further decrease in P concentration. Therefore, 0.125 mmol·L−1 was the tolerance threshold of B. napus L. to low P. With the help of electrophysiological information, the effects of the dynamics of intracellular substances on photosynthesis and growth of B. napus L. under low-P stress can be investigated, and the plant's adaptive response can be revealed. However, the findings of the current hydroponic study are not directly applicable to field conditions with naturally P-deficient soils. [ABSTRACT FROM AUTHOR]

The pertinent study assessed the different photosynthetic activity parameters in spring soft wheat (Triticum aestivum L.) genotypes based on diverse mineral nutrition levels. The dynamics of leaf area growth, photosynthetic potential, and net crop productivity at various developmental stages reached analysis. The determined average correlation between yield and flag leaf area for three research backgrounds showed that not all wheat genotypes responded equally to the mineral fertilizer due to their varied biological characteristics and genetic backgrounds. It was also evident that enhancement in leaf area and photosynthetic parameters appeared in wheat genotypes when applied with complete fertilizer doses. For instance, the following rates emerged for the maximum flag leaf area (12 300 m2 /ha), the total leaf area (17 700 m2 /ha), photosynthetic potential (0.960 million m2 /day), and the net photosynthesis productivity (6.7 g/m2 per day), with the average grain yield on this background was 3.3 t/ha. The increase in the number of nodal roots of spring soft wheat genotypes mainly responded to the different mineral nutrition levels. In the context of a 0.5 calculated dose of mineral fertilizer, seven out of nine wheat lines had 22% more nodal roots, and the utmost calculated dose of mineral fertilizer was 24% more than the control treatment (unfertilized background), which was crucial for increasing the productivity considerably. [ABSTRACT FROM AUTHOR]

This study analyzed the leaf spectral properties and photosynthesis rates of greenhouse-grown bell pepper leaves according to the growth period and leaf position to investigate the changes in carbon assimilation function according to leaf aging. Photosynthesis, growth, transpiration, stomatal conductance, light transmittance, and light reflectance were measured. As the plants' growth progressed, the number of leaves, fresh weight, and dry weight increased, but the specific leaf area decreased, likely due to the increased distribution of assimilates to reproductive organs. The average photosynthesis rate, according to the measured dates, exhibited a high value despite a large standard error, which was likely influenced by measurement errors caused by external environmental factors. The reflectance and transmittance increased from the upper to the middle and bottom leaves, and the absorption ratio decreased in the same order. The green light spectrum (500–580 nm) had a lower absorption ratio than other spectra because the green coloration of the leaves increased the light reflectance of this spectrum. As the PPFD increased where the leaf was positioned higher, the photosynthesis rate, transpiration amount, and stomatal conductance also increased. The higher the leaf position, the higher the photosynthesis rate, the amount of transpiration, and the stomatal conductance. As the CO2 concentration increased, the photosynthesis rate increased, but the transpiration and stomatal conductance changed little, indicating that the gas exchange within leaves was hardly affected by CO2, but the light levels promoted photosynthesis. From the results of this study, the optical properties of the leaves indicate that they are consistent with Lambert–Beer's law, which implies that the length of the optical path is linearly proportional to the number of molecules in the absorption layer. We obtained the light saturation point and CO2 saturation point of bell peppers grown in a greenhouse and were able to determine the physiological changes in the leaves with increasing leaf age. Therefore, based on this information, it appears that a leaf removal model based on the productivity of bell pepper leaves could be developed. [ABSTRACT FROM AUTHOR]

Solar activity has a significant influence on Earth's climate and may drive many biological processes. Here, we measured growth in 11 tree species distributed along an ≈600‐km latitudinal gradient in South‐Central Chile, recording the width of their growth‐rings among periods of maximum (highest number of sunspots) and minimum (lowest number of sunspots) solar activity. In one of these species, Quillaja saponaria, we experimentally assessed three ecophysiological traits (CO2 fixation through photosynthesis [Amax], growth and leaf production) as well as the expression of five genes related to cell wall elongation and expansion following exposure to high and low levels of UV‐B radiation, simulating scenarios of maximum and minimum solar activity, respectively. We found lower tree growth during the periods of maximum solar activity, with this trend being more evident at lower latitudes, where UV‐B radiation is higher. Exposure of Q. saponaria to higher levels of UV‐B affected the ecophysiological parameters, revealing a decrease in Amax, growth and leaf production. In addition, higher levels of UV‐B led to repression in four of the five genes studied. Our results may help foresee environmental scenarios for different plant species associated with solar activity. [ABSTRACT FROM AUTHOR]

Background: Growing evidence demonstrates that the synergistic interaction of far-red light with shorter wavelength lights could evidently improve the photosynthesis efficiency of multiple species. However, whether/how far-red light affects sink organs and consequently modulates the source‒sink relationships are largely unknown. Results: Here, equal intensities of white and far-red lights were added to natural light for grape plantlets to investigate the effects of far-red light supplementation on grapevine growth and carbon assimilate allocation, as well as to reveal the underlying mechanisms, through physiological and transcriptomic analysis. The results showed that additional far-red light increased stem length and carbohydrate contents in multiple organs and decreased leaf area, specific leaf weight and dry weight of leaves in comparison with their counterparts grown under white light. Compared to white light, the maximum net photosynthetic rate of the leaves was increased by 31.72% by far-red light supplementation, indicating that far-red light indeed elevated the photosynthesis efficiency of grapes. Transcriptome analysis revealed that leaves were most responsive to far-red light, followed by sink organs, including stems and roots. Genes related to light signaling and carbon metabolites were tightly correlated with variations in the aforementioned physiological traits. In particular, VvLHCB1 is involved in light harvesting and restoring the balance of photosystem I and photosystem II excitation, and VvCOP1 and VvPIF3, which regulate light signal transduction, were upregulated under far-red conditions. In addition, the transcript abundances of the sugar transporter-encoding genes VvSWEET1 and VvSWEET3 and the carbon metabolite-encoding genes VvG6PD, VvSUS7 and VvPGAM varied in line with the change in sugar content. Conclusions: This study showed that far-red light synergistically functioning with white light has a beneficial effect on grape photosystem activity and is able to differentially affect the growth of sink organs, providing evidence for the possible addition of far-red light to the wavelength range of photosynthetically active radiation (PAR). [ABSTRACT FROM AUTHOR]

Background and aims: Hakea prostrata (Proteaceae) is a highly phosphorus-use-efficient plant native to southwest Australia. It maintains a high photosynthetic rate at low leaf phosphorus (P) and exhibits delayed leaf greening, a convergent adaptation that increases nutrient-use efficiency. This study aimed to provide broad physiological and gene expression profiles across leaf development, uncovering pathways leading from young leaves as nutrient sinks to mature leaves as low-nutrient, energy-transducing sources. Methods: To explore gene expression underlying delayed greening, we analysed a de novo transcriptome for H. prostrata across five stages of leaf development. Photosynthesis and respiration rates, and foliar pigment, P and nitrogen (N) concentrations were determined, including the division of P into five biochemical fractions. Key results: Transcripts encoding functions associated with leaf structure generally decreased in abundance across leaf development, concomitant with decreases in foliar concentrations of 85% for anthocyanins, 90% for P and 70% for N. The expression of genes associated with photosynthetic function increased during or after leaf expansion, in parallel with increases in photosynthetic pigments and activity, much later in leaf development than in species that do not have delayed greening. As leaves developed, transcript abundance for cytosolic and mitochondrial ribosomal proteins generally declined, whilst transcripts for chloroplast ribosomal proteins increased. Conclusions: There was a much longer temporal separation of leaf cell growth from chloroplast development in H. prostrata than is found in species that lack delayed greening. Transcriptome-guided analysis of leaf development in H. prostrata provided insight into delayed greening as a nutrient-saving strategy in severely phosphorus-impoverished landscapes. [ABSTRACT FROM AUTHOR]

SUMMARY: Plants grown under low magnesium (Mg) soils are highly susceptible to encountering light intensities that exceed the capacity of photosynthesis (A), leading to a depression of photosynthetic efficiency and eventually to photooxidation (i.e., leaf chlorosis). Yet, it remains unclear which processes play a key role in limiting the photosynthetic energy utilization of Mg‐deficient leaves, and whether the plasticity of A in acclimation to irradiance could have cross‐talk with Mg, hence accelerating or mitigating the photodamage. We investigated the light acclimation responses of rapeseed (Brassica napus) grown under low‐ and adequate‐Mg conditions. Magnesium deficiency considerably decreased rapeseed growth and leaf A, to a greater extent under high than under low light, which is associated with higher level of superoxide anion radical and more severe leaf chlorosis. This difference was mainly attributable to a greater depression in dark reaction under high light, with a higher Rubisco fallover and a more limited mesophyll conductance to CO2 (gm). Plants grown under high irradiance enhanced the content and activity of Rubisco and gm to optimally utilize more light energy absorbed. However, Mg deficiency could not fulfill the need to activate the higher level of Rubisco and Rubisco activase in leaves of high‐light‐grown plants, leading to lower Rubisco activation and carboxylation rate. Additionally, Mg‐deficient leaves under high light invested more carbon per leaf area to construct a compact leaf structure with smaller intercellular airspaces, lower surface area of chloroplast exposed to intercellular airspaces, and CO2 diffusion conductance through cytosol. These caused a more severe decrease in within‐leaf CO2 diffusion rate and substrate availability. Taken together, plant plasticity helps to improve photosynthetic energy utilization under high light but aggravates the photooxidative damage once the Mg nutrition becomes insufficient. Significance Statement: Plants grown under low Mg soils are highly susceptible to excessive light intensity, resulting in photooxidation and subsequent leaf chlorosis. The results indicated that plant plasticity, such as increasing Rubisco content and gm, helps to improve photosynthetic energy utilization under high light but aggravates the photooxidative damage once the Mg nutrition becomes insufficient. [ABSTRACT FROM AUTHOR]

In this study, we evaluated the impact of brown seaweed extract (Ecklonia maxima) on the morphology and physiology of three different plant species. We conducted experiments using two types of fertilizers: an artificial fertilizer (0.1 g/L) and a biological extract of brown seaweed (Ecklonia maxima) at two concentrations (C1 at 1 mL/L and C2 at 2.5 mL/L). For melon, the application of C1 resulted in significant improvements in photosynthesis parameters, total chlorophyll content, and overall plant growth. When C2 was applied, it further enhanced these parameters, leading to a notable increase in shoot phytomass. In the case of cucumber, C1 led to increased resource allocation towards stems and leaves. Conversely, C2 increased the number of green leaves and contributed to higher shoot phytomass. For tomato plants, the application of C1 resulted in a slight increase in photosynthesis, but it did not significantly impact leaf growth. On the other hand, C2 induced a modest increase in photosynthesis, chlorophyll content, and root growth. In summary, our findings indicate that brown seaweed extract has a discernible influence on the physiology of the studied plants. However, the specific effects on resource allocation largely depend on the plant species and the concentration of the extract applied. [ABSTRACT FROM AUTHOR]

Background and Aims Plasticity of leaf growth and photosynthesis is an important strategy of plants to adapt to shading stress; however, their strategy of leaf development to achieve a simultaneous increase in leaf area and photosynthesis under shading remains unknown. Methods In the present study, a pot experiment was conducted using three rapeseed genotypes of Huayouza 50 (HYZ50), Zhongshuang 11 (ZS11) and Huayouza 62 (HYZ62), and the responses of plant growth, leaf morphoanatomical traits, cell wall composition and photosynthesis to shading were investigated. Key Results Shading significantly increased leaf area per plant (LA plant) in all genotypes, but the increase in HYZ62 was greater than that in HYZ50 and ZS11. The greater increment of LA plant in HYZ62 was related to the larger decrease in leaf mass per area (LMA) and leaf density (LD), which were in turn related to less densely packed mesophyll cells and thinner cell walls (T cw). Moreover, shading significantly increased photosynthesis in HYZ62 but significantly decreased it in HYZ50. The enhanced photosynthesis in HYZ62 was related to increased mesophyll conductance (g m) due primarily to thinner cell walls. Conclusions The data presented indicate that the different plasticity of mesophyll cell density, cell wall thickness and cell wall composition in response to shading can dramatically affect leaf growth and photosynthesis. [ABSTRACT FROM AUTHOR]

The establishment of crop growth models enables the simulation of the impacts of environmental changes on crop growth, providing theoretical guidance for exploring the relationship between environmental factors and crop growth. The model used the growth cycle (GC) as the simulation time step and was built upon four submodels: topology, photosynthesis, biomass allocation, and geometric morphology. It was quantitatively utilized the concept of effective accumulated temperature (EAT) and parameters such as sink and expansion rate were used to explain the allometric growth relationships among different organs. The R2 values for the geometric morphological parameters such as leaf length, leaf width, leaf area, and internode volume ranged from 0.78 to 0.94, while the F-values for the regression equations ranged from 1533.53 to 13949.51. The R2 values for simulating leaf, internode, and earhead biomass were 0.62-0.94, 0.74-0.97, and 0.98, respectively, with RMSE values ranging from 0.02 to 0.13 g for leaf biomass, 0.03 to 0.13 g for internode biomass, and 1.71 g for earhead biomass. The results indicated that the model exhibited good performance and reliability in simulating the growth and development of leaves, internodes, and earheads. This provides a solid foundation for the development of a millet model with functional-structural feedback. [ABSTRACT FROM AUTHOR]

Salt stress induces significant loss in crop yield worldwide. Although the growth‐stimulating effects of micronutrient nanoparticles (NPs) application under salinity have been studied, the molecular and biochemical mechanisms underlying these effects are poorly understood. The large size of maize leaf growth zones provides an ideal model system to sample and investigate the molecular and physiological bases of growth at subzonal resolution. Using kinematic analysis, our study indicated that salinity at 150 mM inhibited maize leaf growth by decreasing cell division and expansion in the meristem and elongation zones. Consistently, salinity downregulated cell cycle gene expression (wee1, mcm4, and cyclin‐B2‐4). B2O3 NP (BNP) mitigated the stress‐induced growth inhibition by reducing the decrease in cell division and expansion. BNP also enhanced the photosynthesis‐related parameters. Simultaneously, chlorophyll, phosphoenolpyruvate carboxylase and ribulose‐1,5‐bisphosphate carboxylase/oxygenase were stimulated in the mature zone. Concomitant with growth stimulation by BNP, mineral homeostasis, particularly for B and Ca, was monitored. BNP reduced oxidative stress (e.g., lessened H2O2 generation along the leaf zones and reduced lipid peroxidation in the mature zone) induced by salinity. This resulted from better maintenance of the redox status, that is, increased the glutathione‐ascorbate cycle in the meristem and elongation zones, and flavonoids and tocopherol levels in the mature zone. Our study has important implications for assessing the salinity stress impact mitigated by BNP on maize growth, providing a basis to improve the resilience of crop species under salinity stress conditions. [ABSTRACT FROM AUTHOR]

Salt stress is a major adverse environmental factor limiting plant growth. Nitrogen (N) application is an effective strategy to alleviate the negative effects of salt stress on plants. To improve the knowledge of the mechanism of N application on alleviating salt stress on rapeseed seedlings, a pot experiment was conducted with four N application treatments (0, 0.1, 0.2, and 0.3 g N kg-1 soil, referred to as N0, N1, N2, and N3, respectively) and exposed to non-salt stress (0 g NaCl kg-1 soil, referred to as S0) and salt stress (3 g NaCl kg-1 soil, referred to as S1) conditions. The results indicated that in comparison with non-salt stress, salt stress increased the Na content (236.53%) and reactive oxygen species (ROS) production such as hydrogen peroxide (H2O2) (30.26%), resulting in cell membrane lipid peroxidation characterized by an increased content of malondialdehyde (MDA) (122.32%) and suppressed photosynthetic rate (15.59%), finally leading to inhibited plant growth such as shorter plant height, thinner root neck, lower leaf area, and decreased dry weight. N application improved the plant growth, and the improvement by N application under salt stress was stronger than that under non-salt stress, suggesting that rapeseed seedlings exposed to salt stress are more sensitive to N application and require N to support their growth. Moreover, seedlings exposed to salt stress under N application showed lower ROS accumulation; increased photosynthesis; higher antioxidants such as catalase (CAT), superoxide dismutase (SOD), glutathione reductase (GR), and ascorbic acid (AsA); and greater accumulation of osmotic substances including soluble protein, soluble sugar, and proline, as compared with seedlings without N application. In particular, the best improvement by N application under salt stress occurred at the N2 level, while too high N application could weaken the improvement due to inhibited N metabolism. In summary, this study suggests that moderate N application can improve photosynthesis, antioxidants, and osmoregulation to alleviate the adverse effects of salt stress in rapeseed seedlings. [ABSTRACT FROM AUTHOR]

The engineering of carbon nanotubes in the last decades resulted in a variety of applications in electronics, electrochemistry, and biomedicine. A number of reports also evidenced their valuable application in agriculture as plant growth regulators and nanocarriers. In this work, we explored the effect of seed priming with single-walled carbon nanotubes grafted with Pluronic P85 polymer (denoted P85-SWCNT) on Pisum sativum (var. RAN-1) seed germination, early stages of plant development, leaf anatomy, and photosynthetic efficiency. We evaluated the observed effects in relation to hydro- (control) and P85-primed seeds. Our data clearly revealed that seed priming with P85-SWCNT is safe for the plant since it does not impair the seed germination, plant development, leaf anatomy, biomass, and photosynthetic activity, and even increases the amount of photochemically active photosystem II centers in a concentration-dependent manner. Only 300 mg/L concentration exerts an adverse effect on those parameters. The P85 polymer, however, was found to exhibit a number of negative effects on plant growth (i.e., root length, leaf anatomy, biomass accumulation and photoprotection capability), most probably related to the unfavorable interaction of P85 unimers with plant membranes. Our findings substantiate the future exploration and exploitation of P85-SWCNT as nanocarriers of specific substances promoting not only plant growth at optimal conditions but also better plant performance under a variety of environmental stresses. [ABSTRACT FROM AUTHOR]

[Objectives] The purpose of this study was to investigate the regulation and mechanism of hydrogen-rich water (HRW)on the growth and photosynthesis of strawberry (Fragaria×ananassa Duch.). This would benefit agriculture by the application of HRW. [Methods]HRW was used to irrigate strawberries, and parameters such as leaf growth, photosynthetic gas exchange and photosynthetic efficiency were determined. Surface water irrigation was as the control. [Results]After the treatment, the leaf area of strawberries increased, the dry weight and fresh weight of leaves increased by 57.7% and 60.4%, respectively, and the relative growth rate and net assimilation rate increased by 50.0% and 59.9%, respectively, indicating that HRW had a significant effect in promoting strawberry growth. After HRW treatment, the chlorophyll a content increased by 14.4%, the chlorophyll b content did not change significantly, and the net photosynthetic rate of leaves increased by 22.3%, the contents of soluble sugar, glucose and sucrose in leaves significantly increased. After HRW treatment, the electron transport rate of PSⅡ increased but was not significant, while the significant decrease of quantum yield of photosystems Ⅱ nonregulatory energy dissipation Y(NO)indicated that the protection and regulation ability of the PSⅡ of strawberry leaves was improved. While the electron transport rate of PSⅠ and effective photochemical quantum yield Y(I) significantly increased, suggesting that the cyclic electron flow of PSⅠ was improved. Further analysis showed that the transmembrane proton gradient(ΔpH)was significantly higher than that of the control, accounting for the main part of proton motive force, and the ATP content increased by 43.9% compared with the control, confirming the cyclic electron flow results. [Conclusions]Hydrogen-rich water can promote growth and photosynthesis of strawberry leaf by enhancing cyclic photosynthesis electron flow. [ABSTRACT FROM AUTHOR]

To follow the rapid physiological events of the osmotic adjustment (OA) known as a mechanism adaptation of leaf growth to water stress, three-weeks old maize plants Zea mays subsp. mays were exposed to water stress by the addition of polyethylene glycol (PEG) 6000 to the hydroponics solution. The water deficiency caused a quick cessation of elongation rate measured on the 6th growing leaf, as a result of turgor decrease. For this period, the stomatal conductance was maintained temporarily before going down partially, while the photosynthesis continued during stress. After ~30 min. the osmotic potential (?p) started to decrease. Thus, the OA was quickly generated, turgor recovered, and returned to its previous level before the stress. Simultaneously, the leaf elongation rate (LER) partially recovered. The recovery of turgor was quite associated with the osmotic adjustment. In parallel, with the fast increase of the abscisic acid (ABA) in growing not transpiring leaf, with the partial opening of stomata in transpiring leaf, that makes the important connotation. [ABSTRACT FROM AUTHOR]

In Ranunculus asiaticus L., vernalization of propagation material is a common practice for the production scheduling of cut flowers, however little is known about the plant physiology and metabolism of this species as affected by cold treatments. We investigated the influence of two hybrids, MBO and MDR, and three preparation procedures of tuberous roots, only rehydration (control, C), and rehydration plus vernalization at 3.5 °C for 2 weeks (V2) and for 4 weeks (V4), on plant growth and flowering, leaf photosynthesis, and leaf metabolic profile in plants grown in pot in a cold greenhouse. Net photosynthesis (NP) was higher in MDR than in MBO. In the two genotypes, the NP did not change in V2 and increased in V4 compared to C in MBO, while was unaffected by vernalization in MDR. Quantum yield of PSII electron transport (ΦPSII), linear electron transport rate (ETR) and non-photochemical quenching (NPQ) did not differ in the two hybrids, whereas maximal PSII photochemical efficiency (Fv/Fm) was higher in MBO than in MDR. Fluorescence indexes were unaffected by the preparation procedure, except for ETR, which decreased in V2 compared to C and V4 in MDR. A significant interaction between genotype and preparation procedure was found in plant leaf area, which was reduced only in V4 in MBO, while decreased in both the vernalization procedures in MDR. In Control plants, flowering started in 65 days in MBO and 69 days in MDR. Compared to controls, both the vernalization treatments anticipated flowering in MDR, while they were detrimental or only slightly efficient in promoting flowering in MBO. Vernalization always reduced the quality of flower stems in both the hybrids. [ABSTRACT FROM AUTHOR]

Background: Silica nanoparticles (SiNPs) have been demonstrated to have beneficial effects on plant growth and development, especially under biotic and abiotic stresses. However, the mechanisms of SiNPs-mediated plant growth strengthening are still unclear, especially under field condition. In this study, we evaluated the effect of SiNPs on the growth and sugar and hormone metabolisms of wheat in the field. Results: SiNPs increased tillers and elongated internodes by 66.7% and 27.4%, respectively, resulting in a larger biomass. SiNPs can increase the net photosynthetic rate by increasing total chlorophyll contents. We speculated that SiNPs can regulate the growth of leaves and stems, partly by regulating the metabolisms of plant hormones and soluble sugar. Specifically, SiNPs can increase auxin (IAA) and fructose contents, which can promote wheat growth directly or indirectly. Furthermore, SiNPs increased the expression levels of key pathway genes related to soluble sugars (SPS, SUS, and α-glucosidase), chlorophyll (CHLH, CAO, and POR), IAA (TIR1), and abscisic acid (ABA) (PYR/PYL, PP2C, SnRK2, and ABF), whereas the expression levels of genes related to CTKs (IPT) was decreased after SiNPs treatment. Conclusions: This study shows that SiNPs can promote wheat growth and provides a theoretical foundation for the application of SiNPs in field conditions. [ABSTRACT FROM AUTHOR]

Antibiotic pollution has become a global environmental pollution problem. Chlorophyll fluorescence is one of the most important indicators reflecting the degree to which plants are influenced by the environment. Ofloxacin (OFL) is a highly toxic antibiotic pollutant, and there are few reports on the effects of changes in OFL levels on tomato chlorophyll fluorescence parameters. In this study, we investigated the responses of tomato growth, photosynthetic activity and chlorophyll fluorescence kinetics to exogenous OFL exposure (as the concentrations of 0, 2.5, 5, 10 and 20 mg L−1). The results showed that lower concentrations of OFL (2.5 mg L−1) had little impact on tomato growth, while plant growth was inhibited with the OFL concentration increasing. At higher OFL concentrations (5, 10 and 20 mg L−1), chloroplasts ruptured, and chlorophyll became degraded, resulting in leaf etiolation. Furthermore, the photosynthetic and photochemical efficiency and electron transfer rate were significantly inhibited by OFL. Moreover, damage to the oxygen-evolving complex on the donor side of PSⅡ prevented electron transfer from QA to QB and led to photoinhibition. In conclusion, higher OFL concentration reduced photosynthesis by destroying the photosynthetic mechanism in tomato, resulting in tomato leaf etiolation and plant growth inhibition. • Low concentrations of OFL increased tomato seedings shoot growth. • The photosynthesis and chlorophyll fluorescence were significantly inhibited by OFL. • OFL treatment led to increased heat dissipation of light energy. • High dose of ofloxacin destroyed the chloroplast structure. [ABSTRACT FROM AUTHOR]

Photosynthesis is susceptible in response to nitrogen (N) deficiency. However, the acclimation of shade-tolerant and high-N sensitive species to N deficiency is unclear. Leaf morpho-physiological traits, photosynthetic performance related parameters were examined in a shade-tolerant and high-N sensitive species P. notoginseng grown under different N levels. Lower N content and Chl content were recorded in the N0-grown P. notoginseng. The maximum values of leaf morpho-physiological traits, photosynthetic rate, and photosynthetic N use efficiency (PNUE) were obtained in the N15-grown P. notoginseng. Coefficients for leaf N allocation into the carboxylation and light-harvesting system components in the N0-grown plants were significantly higher than others. N0 and N7.5 plants showed higher K phase. N addition decreased the absorption and capture of the light energy per unit area (ABS/RC and TRO/RC) and non-photochemical quenching (NPQ). Photochemical quenching (qP), electron transport rate (ETR), and effective quantum yield of photosystem II (ϕPSII) were reduced in the N0-grown plants. The reduction of light-harvesting and utilization capacity not only leads to a decrease in PNUE, but also induces the damage of PSII reaction center. Overall, the inhibition of leaf growth and photosynthetic capacity is an essential strategy for high-N sensitive and shade-tolerant plants in response to N deficiency. [ABSTRACT FROM AUTHOR]

Houttuynia cordata Thunb. (H. cordata) is a significant medicinal plant in China, known for its strong effects in healthcare and disease treatment. However, wild-harvested H. cordata often accumulates heavy metal contaminants, and currently, there is no environmentally safe method for its cultivation. This study aims to explore the influence of cultivation substrates on the growth, development, and medicinal components of H. cordata , and to elucidate the potential mechanisms underlying the increased biomass of H. cordata under hydroponic conditions using multi-omics techniques. Methodologically, we employed soilless cultivation to ensure medicinal safety and used multi-omics analysis to reveal the differential metabolites and genes associated with various cultivation methods. Our findings indicate that soilless cultivation effectively reduces H. cordata 's accumulation of benzene while maintaining medicinal component levels comparable to traditional soil cultivation. Hydroponically grown H. cordata exhibits significantly higher biomass compared to other methods. The integration of multi-omics analysis shows that differential metabolites and genes in hydroponically grown H. cordata are primarily enriched in nitrogen metabolism and photosynthetic pathways. Additionally, we found that increased nitric oxide content significantly enhances H. cordata 's photosynthesis and gene expression, promoting leaf and root growth. In conclusion, soilless cultivation reduces benzene metabolite levels in H. cordata while preserving its medicinal properties, and hydroponics facilitates its growth and development. This study lays a theoretical foundation for the industrial production of environmentally friendly, uncontaminated medicinal H. cordata. [Display omitted] • Houttuynia cordata Thunb thrives in soilless cultivation, with significant biomass increase. • Soilless cultivation effectively reduces benzene accumulation in H. cordata. • Multi-omics reveals hydroponic regulation mechanisms in H. cordata growth. [ABSTRACT FROM AUTHOR]

Salt marsh ecosystems are underrepresented in process‐based models due to their unique location across the terrestrial–aquatic interface. Particularly, the role of leaf nutrients on canopy photosynthesis (FA) remains unclear, despite their relevance for regulating vegetation growth. We combined multiyear information of canopy‐level nutrients and eddy covariance measurements with canopy surface hyperspectral remote sensing (CSHRS) to quantify the spatial and temporal variability of FA in a temperate salt marsh. We found that FA showed a positive relationship with canopy‐level N at the ecosystem scale and for areas dominated by Spartina cynosuroides, but not for areas dominated by short S. alterniflora. FA showed a positive relationship with canopy‐level P, K, and Na, but a negative relationship with Fe, for areas associated with S. cynosuroides, S. alterniflora, and at the ecosystem scale. We used partial least squares regression (PLSR) with CSHRS and found statistically significant data–model agreements to predict canopy‐level nutrients and FA. The red‐edge electromagnetic region and ∼770 nm showed the highest contribution of variance in PLSR models for canopy‐level nutrients and FA, but we propose that underlying sediment biogeochemistry can complicate interpretation of reflectance measurements. Our findings highlight the relevance of spatial variability in salt marshes vegetation and the promising application of CSHRS for linking information of canopy‐level nutrients with FA. We call for further development of canopy surface hyperspectral methods and analyses across salt marshes to improve our understanding of how these ecosystems will respond to global environmental change. Plain Language Summary: Canopy photosynthesis in salt marshes contributes to the carbon stored in these ecosystems; however, its relationship with canopy‐level nutrients has been underrepresented in models. Reflectance from near surface remote sensing could be a cost‐effective nondestructive tool to monitor canopy photosynthesis and associated nutrients in salt marshes. We combined canopy‐level nutrient information with hyperspectral canopy reflectance to represent the spatial and temporal variability of canopy photosynthesis in a salt marsh in the Mid‐Atlantic cost of the U.S. We found that local variability such as different salt marsh species have an influence on the relationship between canopy photosynthesis and associated nutrients, in consequence the most limiting nutrients for photosynthesis were phosphorus, potassium, and sodium. We propose that underlying sediment biogeochemistry can potentially obscure the expected relationships between plant nutrients and photosynthesis in remote sensing of coastal wetlands. These results open the possibility to use similar reflectance information from airborne or spaceborne platforms to explore these relationships at broader scales. Key Points: Local environmental variability influences the relationship of canopy nutrients with canopy photosynthesis in a salt marsh ecosystemSediment biogeochemistry can obscure expected relationships between plant nutrients and photosynthesis in remote sensing of coastal wetlandsCanopy surface hyperspectral remote sensing is a promising technique for studying vegetation dynamics of salt marshes [ABSTRACT FROM AUTHOR]

Key message: Tomato DWARF14 regulates the development of roots, shoot branches and leaves, and also plays a role in photosynthetic pigment accumulation and photosynthetic capacity. Strigolactones (SLs) are a novel class of plant hormones. DWARF14 (D14) is the only SL receptor identified to date, but it is not functionally analyzed in tomato (Solanum lycopersicum). In the present study, we identified the potential SL receptor in tomato by bioinformatic analysis, which was designated as SlD14. SlD14 was expressed in roots, stems, flowers and developing fruits, with the highest expression level in leaves. sld14 mutant plants produced by the CRISPR/Cas9 system displayed reduced plant height and root biomass, increased shoot branching and altered leaf shape comparing with WT plants. The cytokinin biosynthetic gene ISOPENTENYLTRANSFERASE 3 (SlIPT3), auxin biosynthetic genes FLOOZY (SlFZY) and TRYPTOPHAN AMINOTRANSFERASE RELATED 1 (SlTAR1) and several auxin transport genes SlPINs, which are involved in branch formation, showed higher expression levels in the sld14 plant stem. In addition, sld14 plants exhibited light-green leaves, reduced chlorophyll and carotenoid contents, abnormal chloroplast structure and reduced photosynthetic capacity. Transcriptomic analysis showed that the transcript levels of six chlorophyll biosynthetic genes, three carotenoid biosynthetic genes and numerous chlorophyll a/b-binding protein genes were decreased in sld14 plants. These results suggest that tomato SL receptor gene SlD14 not only regulates the development of roots, shoot branches and leaves, but also plays a role in regulating photosynthetic pigment accumulation and photosynthetic capacity. [ABSTRACT FROM AUTHOR]

Water scarcity is one of the most limiting environmental factors for crop productivity globally, where biochar application can play a role. To test this, a glasshouse experiment was conducted with aged biochar application with water regimes on arbuscular mycorrhizal fungi colonisation, plant growth, phosphorus nutrition and leaf gas exchange in wheat and subterranean clover. Six treatment combinations (two biochar levels of 0 and 6 t ha−1; and three water regimes of well-watered, water-stressed and watering intermittently) were arranged in factorial completely randomized block design with three replications. The wheat and subterranean clover were grown and harvested 14, 24, 34 and 44 days after sowing. In this study, aged biochar had no significant effect on plant growth for both wheat and clover, regardless of water regimes. Shoot and root dry weights increased in well-watered conditions compared to water-stressed conditions. Root length and colonised root length increased with biochar addition for wheat, mostly in well-watered treatment. Phosphorus uptake increased in biochar treatment, and the effect was higher in well-watered conditions. Leaf photosynthetic rate (PN), stomatal conductance (gs), intercellular CO2 concentration (Ci) and transpiration rate (E) increased with biochar addition. For clover, the effect was higher in water-stressed than well-watered conditions. These results suggest that biochar may enhance water availability to clover plants in water-stressed conditions. However, the positive effect of biochar on plant growth under water-stressed conditions, varied with plant species, needs to be explored further in a range of crop species and biochar sources in addition to the material used in the current investigation. [ABSTRACT FROM AUTHOR]

Leaf growth relies on photosynthesis and hydraulics to provide carbohydrates and expansion power; in turn, leaves intercept light and construct organism systems for functioning. Under potassium (K) deficiency stress, leaf area, photosynthesis and hydraulics are all affected by alterations in leaf structure. However, the connection between changes in leaf growth and function caused by the structure under K regulation is unclear. Consequently, the leaf hydraulic conductance (Kleaf) and photosynthetic rate (A) combined with leaf anatomical characteristics of Brassica napus were continuously observed during leaf growth under different K supply levels. The results showed that Kleaf and A decreased simultaneously after leaf area with the increasing K deficiency stress. K deficiency significantly increased longitudinal mesophyll cell investment, leading to a reduced volume fraction of intercellular air‐space (fias) and decreased leaf expansion rate. Furthermore, reduced fias decreased mesophyll and chloroplast surfaces exposed to intercellular airspace and gas phase H2O transport, which induced coordinated changes in CO2 mesophyll conductance and hydraulic conductance in extra‐xylem pathways. Adequate K supply facilitated higher fias through smaller palisade tissue cell density (loose mesophyll cell arrangement) and smaller spongy tissue cell size, which coordinated CO2 and H2O conductance and promoted leaf area expansion. [ABSTRACT FROM AUTHOR]

Polygala fallax Hemsl. (Polygalaceae), a traditional Chinese medicinal species, requires optimal growth conditions for artificial cultivation. Irradiance is one of the primary environmental factors that affects the growth and survival of P. fallax Hemsl. plants, which seemingly grow better under weak irradiance conditions. However, the optimum light intensity for growing P. fallax Hemsl. is not clear. To determine the optimum light intensity for cultivating this medicinal plant species, P. fallax Hemsl. plants from two different habitats were grown and exposed to three shade treatments (50% shade, 70% shade and 90% shade, which resulted in photosynthetically active radiation amounts equal to 662 µmol m-2 s-1, 401 µmol m-2 s-1, and 131 µmol m-2 s-1, respectively) to evaluate survival, growth, leaf photosynthesis, and the main pharmacological active ingredients (saponins) in response to shade. Our results revealed that the P. fallax Hemsl. plants in the different habitats consistently exhibited relatively high photosynthesis rates, biomass, survival rates and saponins under 662 µmol m-2 s-1 created by the 50% shade treatment. We concluded that photosynthetically active radiation of approximately 662 µmol m-2 s-1 is suitable for the cultivation of P. fallax Hemsl. plants. [ABSTRACT FROM AUTHOR]

Enhanced crop growth and yield are the recurring concerns in agricultural field, considering the soaring world population and climate change. Abiotic stresses are one of the major limiting factors for constraining crop production, for several economically important horticultural crops, and contribute to almost 70% of yield gap. Salt stress is one of these unsought abiotic stresses that has become a consistent problem in agriculture over the past few years. Salinity further induces ionic, osmotic, and oxidative stress that result in various metabolic perturbations (including the generation of reactive oxygen, carbonyl, and nitrogen species), reduction in water potential (ψw), distorted membrane potential, membrane injury, altered rates of photosynthesis, leaf senescence, and reduced nitrogen assimilation, among others); thereby provoking a drastic reduction in crop growth and yield. One of the strategies to mitigate salt stress is the use of natural plant extracts (PEs) instead of chemical fertilizers, thus limiting water, soil, and environmental pollution. PEs mainly consist of seeds, roots, shoots, fruits, flowers, and leaves concentrates employed either individually or in mixtures. Since PEs are usually rich in bioactive compounds (e.g., carotenoids, flavonoids, phenolics, etc.), therefore they are effective in regulating redox metabolism, thereby promoting plant growth and yield. However, various factors like plant growth stage, doses applied, application method, soil, and environmental conditions may greatly influence their impact on plants. PEs have been reported to enhance salt tolerance in plants primarily through modulation of signaling signatures and pathways (e.g., Na+, ANNA4, GIPC, SOS3, and SCaBP8 Ca2+ sensors, etc.), and regulation of redox machinery [e.g., superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), non-specific peroxidase (POX), glutathione peroxidase (GPX), peroxiredoxin (Prx), ascorbic acid (AsA), glutathione (GSH), α-tocopherol, etc.]. The current study highlights the role of PEs in terms of their sources, methods of preparation, and mode of action with subsequent physiological changes induced in plants against salinity. However, an explicit mode of action of PEs remains nebulous, which might be explicated utilizing transcriptomics, proteomics, metabolomics, and bioinformatics approaches. Being ecological and economical, PEs might pave the way for ensuring the food security in this challenging era of climate change. [ABSTRACT FROM AUTHOR]

Pistia stratiotes is a cadmium (Cd) hyperaccumulating plant with strong bioaccumulation and translocation capacity for Cd. A hydroponic experiment was used to evaluate the combined effect of Zinc (Zn) and Cd at different concentrations on leaf growth and metabolism of P. stratiotes. This study revealed the physiological defense and metabolic strategy of responses to Zn–Cd co-pollution. With the Zn 50 Cd 1 , Zn 50 Cd 10 , Zn 100 Cd 1, and Zn 100 Cd 10 treatments for 9 d, the relative crown diameter, relative leave number, and ramet number of the plant had no significant difference with the control. Under the compound treatments containing Zn 50 Cd 50 and Zn 100 Cd 50 , the activity of the glyoxalase system and amino acid metabolism in the leaves were inhibited. The leaf photosynthetic apparatus increased heat dissipation to reduce the damage to the photosystem II (PS II) reaction center caused by excess excitation energy under Zn–Cd stress. This safeguarded the balance between the absorption and utilization of light energy. Compared to the control, the Zn and Cd co-pollution for 9 d had no effect on the reduced glutathione (GSH) and oxidized glutathione (GSSG) contents. There was no effect on the dehydroascorbate reductase (DHAR) and glutathione reductase (GR) activities, but there was increased ascorbate peroxidase (APX) activity and oxidized ascorbic acid (DHA) content. These increased the antioxidant capacity of the ascorbate-glutathione (AsA-GSH) cycle. The treated plants also had increased levels of carnosol and substances related to lipid metabolism including 9, 10-Dihydroxystearate, Prostaglandin G2, Sphingosine, and 13-L-Hydroperoxylinoleic acid, maintaining the cell stability and resistance to the Zn–Cd stress. [Display omitted] • The redox reaction equilibrium of glutathione maintained the antioxidant stability. • Increased carnosol and lipid metabolism were conducive to zinc-cadmium tolerance. • Pistia stratiotes can be used for phytoremediation of zinc-cadmium polluted water. [ABSTRACT FROM AUTHOR]

Leaf aging is a significant process during herbaceous plant senescence, which is influenced by various internal and external factors. During leaf aging, chlorophyll catabolism is one of the most important metabolism pathways and results in leaf yellowing. Understanding the underlying mechanism is important for the regulation of senescence in tobacco leaf. However, there are few studies on explaining tobacco leaf senescence from the proteomics level. Here, photosynthesis experiments, cell ultrastructure, and proteomics were used to study tobacco leaves of different growth stages. We applied iTRAQ-based quantitative proteomics and parallel reaction monitoring (PRM) to determine the accumulation of proteins in aging tobacco leaves. Overall, we screened 4747 proteins. The result of KEGG pathways analysis showed that differently expressed proteins (DEPs) were involved in four pathways: metabolic pathways, biosynthesis of secondary metabolites, microbial metabolism in diverse environments, and starch and sucrose metabolism. This would be first report based on iTRAQ-PRM technique, in which we identified proteins related to photosynthesis showed a differently expressed during senescence stage in flue-cured tobacco plants. [ABSTRACT FROM AUTHOR]

In plant chloroplasts, photosystem II (PSII) complexes, together with light‐harvesting complex II (LHCII), form various PSII‐LHCII supercomplexes (SCs). This process likely involves immunophilins, but the underlying regulatory mechanisms are unclear. Here, by comparing Arabidopsis thaliana mutants lacking the chloroplast lumen‐localized immunophilin CYCLOPHILIN28 (CYP28) to wild‐type and transgenic complemented lines, we determined that CYP28 regulates the assembly and accumulation of PSII‐LHCII SCs. Compared to the wild type, cyp28 plants showed accelerated leaf growth, earlier flowering time, and enhanced accumulation of high molecular weight PSII‐LHCII SCs under normal light conditions. The lack of CYP28 also significantly affected the electron transport rate. Blue native‐polyacrylamide gel electrophoresis analysis revealed more Lhcb6 and less Lhcb4 in M‐LHCII‐Lhcb4‐Lhcb6 complexes in cyp28 versus wild‐type plants. Peptidyl‐prolyl cis/trans isomerase (PPIase) activity assays revealed that CYP28 exhibits weak PPIase activity and that its K113 and E187 residues are critical for this activity. Mutant analysis suggested that CYP28 may regulate PSII‐LHCII SC accumulation by altering the configuration of Lhcb6 via its PPIase activity. Furthermore, the Lhcb6‐P139 residue is critical for PSII‐LHCII SC assembly and accumulation. Therefore, our findings suggest that CYP28 likely regulates PSII‐LHCII SC assembly and accumulation by altering the configuration of P139 of Lhcb6 via its PPIase activity. [ABSTRACT FROM AUTHOR]

A better understanding of how climate affects growth in tree species is essential for improved predictions of forest dynamics under climate change. Long‐term climate averages (mean climate) drive spatial variations in species' baseline growth rates, whereas deviations from these averages over time (anomalies) can create growth variation around the local baseline. However, the rarity of long‐term tree census data spanning climatic gradients has so far limited our understanding of their respective role, especially in tropical systems. Furthermore, tree growth sensitivity to climate is likely to vary widely among species, and the ecological strategies underlying these differences remain poorly understood. Here, we utilize an exceptional dataset of 49 years of growth data for 509 tree species across 23 tropical rainforest plots along a climatic gradient to examine how multiannual tree growth responds to both climate means and anomalies, and how species' functional traits mediate these growth responses to climate. We show that anomalous increases in atmospheric evaporative demand and solar radiation consistently reduced tree growth. Drier forests and fast‐growing species were more sensitive to water stress anomalies. In addition, species traits related to water use and photosynthesis partly explained differences in growth sensitivity to both climate means and anomalies. Our study demonstrates that both climate means and anomalies shape tree growth in tropical forests and that species traits can provide insights into understanding these demographic responses to climate change, offering a promising way forward to forecast tropical forest dynamics under different climate trajectories. [ABSTRACT FROM AUTHOR]

This study investigates differential responses of Aegiceras corniculatum and Kandelia candel mangrove species, using physiological capacitance (CP), photosynthetic, and growth parameters under different salt stress and re-watering conditions. Experiment was conducted at various NaCl levels. The Results indicated that CP was significantly affected in stress phase due to the limitation of salt storage capacity of the vacuole. Although A. corniculatum has a secreting effect, the solute concentration in vacuole was significantly higher than K. candel at M and H treatment, because their volume of vacuole was lower than K. candel species. In the re-watering phase, CP values of both species increased at M-L and H-M treatments respectively. Furthermore, CP was positively correlated with net photosynthesis and stomatal conductance. This finding suggests that the concentration of solute in vacuole is an important factor controlling photosynthesis and growth parameters, and CP can better represent salt concentration in the plant leaf. [ABSTRACT FROM AUTHOR]

Carbon sequestration is a key ecosystem service provided by forests. Inventory data based on individual trees are considered to be the most accurate method for estimating forest productivity. However, the estimations of forest photosynthesis from inventory data remain understudied, particularly when considering the growth and development of individual trees under the background of global change.Here, we used the leaf growth process with phenology and non‐structural carbohydrates (NSC) storage to revise an individual‐tree‐based carbon model, FORCCHN. This model couples leaf development and biomass to quantify gross primary productivity (GPP) in the forests, where growth is decoupled from photosynthesis in daily step. The model was initialized with inventory‐based forest data rather than the more widely used satellite‐based data.We tested the model against measured above‐ground woody biomass, growth of leaf biomass, daily gross ecosystem exchange (GEE) and yearly GEE at five representative forest sites in the Northern Hemisphere. We also compared the results from the original model and the revised model at five forest sites. Including leaf growth dynamics and inventory‐based initialization improved the predicted performance (r2) of GPP by an average of 33%.Synthesis and applications. Our results suggest that the appropriate vegetation data sources (i.e. inventory or satellite selection) and the effective predictions of the growth process should be considered when developing future carbon cycle models and forest carbon estimation options. Applying and improving such carbon models to evaluate carbon sequestration is an important part of forest carbon sink management. [ABSTRACT FROM AUTHOR]

Adesmia bijuga Phil. is an endemic and endangered shrub species of central Chile. Its potential shade intolerance is one of the leading hypotheses for its vigor loss when the species grows beneath closed canopies. The objective of this study was to assess the growth and physiological acclimation to the shade of young plants of A. bijuga. A nursery experiment was established with three light levels based on the interception of photosynthetic active radiation (PAR) (TRT0: control at full sun; TRT60: 60% shaded; TRT90: 90% shaded), and maintained for 71 days during the summer season. Growth and leaf morpho-physiological responses were evaluated at the beginning, at the middle, and at the end of the experiment. The shading treatment increased plant height (H), live crown percentage (Lcrown), and specific leaf area (SLA) compared to the control treatment at full sun. However, light-saturated photosynthetic rate (Amax), dark respiration rate (Rd), and light compensation point (Gi) were higher in TRT60 than in the other treatments, while no differences were found among treatments for the apparent quantum yield (a). At this stage of plant development, our results suggest high acclimation plasticity of A. bijuga to light levels; however, a semi-shade environment (i.e., TRT60) favored a better performance of the species. [ABSTRACT FROM AUTHOR]

The present study was carried out to monitor leaf growth, foliar emission, and the daily photosynthesis behavior of sisal plants cv Ceniza. In a commercial crop, sisal plants were selected and monitored weekly to determine increase in number, length, width, and thickness of the leaves, during a 154 day period. On two occasions during the experimental period, gas exchange rates were also monitored during the light and dark periods. The results allowed determining a phyllochron of 8.65 days. Gas exchange monitoring detected low stomatal conductance rates during the light period. However, starting at 15:30 h, stomatal conductance substantially increased, remaining at maximum levels throughout the dark period, and, subsequently, decreased from 09:30 h, the following light period. A high correlation of stomatal conductance with vapor pressure deficit and leaf temperature was found. Maximum CO2 fixation rates varied between 12.2 and 14.5 µmol m-2 s-1, recorded between 19:19 and 19:26 h. The results corroborate the CAM metabolism of sisal plants cv Ceniza. [ABSTRACT FROM AUTHOR]

Accurate acquisition of plant phenotypic information has raised long-standing concerns in support of crop breeding programs. Different methods have been developed for high throughput plant phenotyping, while they mainly focused on the canopy level without considering the spatiotemporal heterogeneity at different canopy layers and growth stages. This study aims to phenotype spatiotemporal heterogeneity of chlorophyll (Chl) content and fluorescence response within rice leaves and canopies. Multipoint Chl content and high time-resolved Chl a fluorescence (ChlF) transient (OJIP transient) of rice plants were measured at different nitrogen levels and growth stages. Results showed that the Chl content within the upper leaves exhibited an increasing trend from the basal to the top portions but a decreasing pattern within the lower leaves at the most growth stages. Leaf Chl content within the rice canopy was higher in the lower leaves in the vegetative phase, while from the initial heading stage the pattern gradually reversed with the highest Chl content appearing in the upper leaves. Nitrogen supply mainly affects the occurrence time of the reverse vertical pattern. This could be the result of different nutritional demands of leaves transforming from sinks to sources, and it was further confirmed by the fall of the JI phase of OJIP transient in the vegetative phase and the rise in the reproductive phase. We further deduced that the vertical distribution of Chl content could have a defined pattern at a specific growth stage. Furthermore, the reduction of end acceptors at photosystem I (PSI) electron acceptor side per cross section (RE0/CS) was found to be a potential sensitive predictor for identifying the vertical heterogeneity of leaf Chl content. These findings provide prior knowledge on the vertical profiles of crop physiological traits, which explore the opportunity to develop more efficient plant phenotyping tools for crop breeding. [ABSTRACT FROM AUTHOR]

To copy with highly heterogeneous light environment, plants can regulate photosynthesis locally and systemically, thus, maximizing the photosynthesis of individual plants. Therefore, we speculated that local weak light may induce the improvement of photosynthesis in adjacent illuminated leaves in plants. In order to test this hypothesis, maize seedlings were partially shaded, and gas exchange, chlorophyll a fluorescence and biochemical analysis were carefully assessed. It was shown that local shading exacerbated the declines in the photosynthetic rates, chlorophyll contents, electron transport and carbon assimilation‐related enzyme activities in shaded leaves as plants growth progressed. While, the decreases of these parameters in adjacent illuminated leaves of shaded plants were considerably alleviated compared to the corresponding leaves of control plants. Obviously, the photosynthesis in adjacent illuminated leaves in shaded plants was improved by local shading, and the improvement in adjacent lower leaves was larger than that in adjacent upper ones. As growth progressed, local shading induced higher abscisic acid contents in shaded leaves, but it alleviated the increase in the abscisic acid contents in adjacent leaves in shaded plants. Moreover, the difference in sugar content between shaded leaves and adjacent illuminated ones was gradually increased. Consequently, local weak light suppressed the photosynthesis in shaded leaves, while it markedly improved the photosynthesis of adjacent illuminated ones. Sugar gradient between shaded leaves and adjacent illuminated ones might play a key role in photosynthetic regulation of adjacent illuminated leaves. [ABSTRACT FROM AUTHOR]

This work aims to study rapid osmotic adjustment, in order to simplify and follow this mechanism with the changes of various sugars and potassium in parallel with growth and photosynthesis measurements. Four durum wheat varieties of Triticum turgidum subsp. durum L. designated as: "Inrat-var", "MBB-var", "OZ-var", and "Waha-var" were growing in continuously aerated-nutrient-solutions. The kinetic of the leaf elongation for leaf 3 were measured by the linear variable differential transducer (LVDT); osmotic potential (OP), carbohydrates, and potassium (K+) concentrations. Growth recovered rapidly after a sudden full after stress. A considerable difference was noted in the recuperation (%) of the leaf elongation rate (LER) under the four varieties. The variation in the partial recuperation of LER was, therefore, associated with the aptitude of osmotic adjustment in the elongation zone (EZ) of the leaf growth. Osmotic adjustment is associated with soluble sugars and potassium accumulation. Compared to the accumulation of these solutes in the mature zone (MZ) and the photosynthesis process, several ideas related to this accumulation mechanism can be assumed among them, this accumulation process cannot be considered as a direct result of the reduction of the growth. Rather, it might be as the result of their mobilization from the MZ of growing leaf or other expanded leaves. The accumulation of these sugars probably is uncoupled with direct photosynthesis activity. [ABSTRACT FROM AUTHOR]

Forest ecosystems are an important sink for terrestrial carbon sequestration. Hence, accurate modeling of the intra‐ and interannual variability of forest photosynthetic productivity remains a key objective in global biology. Applying climate‐driven leaf phenology and growth in models may improve predictions of the forest gross primary productivity (GPP). We used a dynamic non‐structural carbohydrates (NSC) model (FORCCHN2) that couples leaf development and phenology to investigate the relationships among photosynthesis and environmental factors. FORCCHN2 simulates spring and autumn phenological events from heat and chilling, respectively. Leaf area index data from satellites along with climate data estimated localized phenological parameters. NSC limitation, immediate temperature, accumulated heat, and growth potential comprised a daily leaf‐growth model. Functionally, leaf growth was decoupled from photosynthesis. Leaf biomass determined overall photosynthetic production. We compared this model with outputs of the other six terrestrial biospheric models and with observations from the North American Carbon Program Site Interim Synthesis in 18 forest sites. This model improved the predicted performance of yearly GPP with a 57%–210% increase in correlation (median) and up to a 102% reduction in biases (median), compared to three prognostic models and three prescribed models. At the North America continental scale, the model predicted the average annual GPP of 7.38 Pg C/year from forest ecosystems during 1985–2016. The results showed an increasing trend of GPP in North America (1.0 Pg C/decade). The inclusion of climate‐driven phenology and growth has a significant potential for improving dynamic vegetation models, and promotes a further understanding of the complex relationship between environment and photosynthesis. [ABSTRACT FROM AUTHOR]

Mesembryanthemum crystallinum L. is a nutritious edible facultative halophyte. This study aimed to investigate the physiology and quality of M. crystallinum L. grown under different salinities and salt-priming conditions. All plants were first grown in 10% artificial seawater (ASW) for 10 days. After that, some plants remained in 10% ASW while the others were transferred to 20%, 30%, 40%, or 50% ASW for another 10 days. Some plants also underwent a salt priming by transferring them gradually from 10% to 100% ASW over a span of 10 days (defined as salt primed). All plants were green and healthy. However, there were reductions in shoot and root productivity, leaf growth, and water content, but also an increase in leaf succulence after transferring plants to higher salinities. The salt-primed plants showed higher photosynthetic light use efficiency with higher chlorophyll concentration compared to other plants. The concentrations of proline, ascorbic acid (ASC), and total phenolic compounds (TPC) increased as percentages of ASW increased. The salt-primed plants switched from C3 to crassulacean acid metabolism photosynthesis and accumulated the greatest amounts of proline, ASC, and TPC. In conclusion, higher salinities and salt priming enhance the nutritional quality of M. crystallinum L. but compromises productivity.

To understand the growth response to drought, we performed a proteomics study in the leaf growth zone of maize (Zea mays L.) seedlings and functionally characterized the role of starch biosynthesis in the regulation of growth, photosynthesis and antioxidant capacity, using the shrunken-2 mutant (sh2), defective in ADP-glucose pyrophosphorylase. Drought altered the abundance of 284 proteins overrepresented for photosynthesis, amino acid, sugar and starch metabolism, and redox-regulation. Changes in protein levels correlated with enzyme activities (increased ATP synthase, cysteine synthase, starch synthase, RuBisCo, peroxiredoxin, glutaredoxin, thioredoxin and decreased triosephosphate isomerase, ferredoxin, cellulose synthase activities, respectively) and metabolite concentrations (increased ATP, cysteine, glycine, serine, starch, proline and decreased cellulose levels). The sh2 mutant showed a reduced increase of starch levels under drought conditions, leading to soluble sugar starvation at the end of the night and correlating with an inhibition of leaf growth rates. Increased RuBisCo activity and pigment concentrations observed in WT, in response to drought, were lacking in the mutant, which suffered more oxidative damage and recovered more slowly after re-watering. These results demonstrate that starch biosynthesis contributes to maintaining leaf growth under drought stress and facilitates enhanced carbon acquisition upon recovery. [ABSTRACT FROM AUTHOR]

Arabidopsis AINTEGUMENTA (ANT), an AP2 transcription factor, is known to control plant growth and floral organogenesis. In this study, our transcriptome analysis and in situ hybridization assays of maize embryonic leaves suggested that maize ANT1 (ZmANT1) regulates vascular development. To better understand ANT1 functions, we determined the binding motif of ZmANT1 and then showed that ZmANT1 binds the promoters of millet SCR1, GNC, and AN3, which are key regulators of Kranz anatomy, chloroplast development, and plant growth, respectively. We generated a mutant with a single-codon deletion and two frameshift mutants of the ANT1 ortholog in the C4millet Setaria viridis by the CRISPR/Cas9 technique. The two frameshift mutants displayed reduced photosynthesis efficiency and growth rate, smaller leaves, and lower grain yields than wild-type (WT) plants. Moreover, their leaves sporadically exhibited distorted Kranz anatomy and vein spacing. Conducting transcriptomic analysis of developing leaves in the WT and the three mutants we identified differentially expressed genes (DEGs) in the two frameshift mutant lines and found many downregulated DEGs enriched in photosynthesis, heme, tetrapyrrole binding, and antioxidant activity. In addition, we predicted many target genes of ZmANT1 and chose 13 of them to confirm binding of ZmANT1 to their promoters. Based on the above observations, we proposed a model for ANT1 regulation of cell proliferation and leaf growth, vascular and vein development, chloroplast development, and photosynthesis through its target genes. Our study revealed biological roles of ANT1 in several developmental processes beyond its known roles in plant growth and floral organogenesis. [ABSTRACT FROM AUTHOR]

Changes in leaf length, width, area, weight, chlorophyll and carotenoids contents, and photosynthetic variables with different leaf positions were investigated in fruit cucumber. Plants were grown on rockwool slabs in an environmentally controlled greenhouse and irrigated by drip fertigation. Leaf measurements were conducted from the first to the 15th leaf (the oldest to the youngest). The results showed that fresh weight per unit leaf area decreased from the second to the 15th leaf. Changes in cucumber leaf length, width, and area followed quadratic models from the first to the 15th leaf. The quadratic models of leaf length, width, and area fit the measurements well, with R2 values of 0.925, 0.951, and 0.955, respectively. The leaf chlorophyll a and b and carotenoid contents increased from the oldest leaf (first leaf) to the youngest leaf and decreased after reaching the highest values. Changes in the net photosynthetic rate (Pn) also followed the quadratic model from the first to the 15th leaf, with R2 values of 0.975. The leaf transpiration rate (Tr) increased from the first to the 14th leaf. Our results revealed patterns in leaf growth and photosynthetic changes at different leaf positions in fruit cucumber and improved our understanding of the growth and development of fruit cucumber in the greenhouse production system. [ABSTRACT FROM AUTHOR]

By modifying two genes involved in lipid biosynthesis and storage [cysteine oleosin (cys-OLE)/diacylglycerol O -acyltransferase (DGAT)], the accumulation of stable lipid droplets in perennial ryegrass (Lolium perenne) leaves was achieved. Growth, biomass allocation, leaf structure, gas exchange parameters, fatty acids, and water-soluble carbohydrates were quantified for a high-expressing cys-OLE/DGAT ryegrass transformant (HL) and a wild-type (WT) control grown under controlled conditions with 1–10 mM nitrogen (N) supply at ambient and elevated atmospheric CO2. A dramatic shift in leaf carbon (C) storage occurred in HL leaves, away from readily mobilizable carbohydrates and towards stable lipid droplets. HL exhibited an increased growth rate, mainly in non-photosynthetic organs, leading to a decreased leaf mass fraction. HL leaves, however, displayed an increased specific leaf area and photosynthetic rate per unit leaf area, delivering greater overall C capture and leaf growth at high N supply. HL also exhibited a greater photosynthesis response to elevated atmospheric CO2. We speculate that by behaving as uniquely stable microsinks for C, cys-OLE-encapsulated lipid droplets can reduce feedback inhibition of photosynthesis and drive greater C capture. Manipulation of many genes and gene combinations has been used to increase non-seed lipid content. However, the cys-OLE/DGAT technology remains the only reported case that increases plant biomass. We contrast cys-OLE/DGAT with other lipid accumulation strategies and discuss the implications of introducing lipid sinks into non-seed organs for plant energy homeostasis and growth. [ABSTRACT FROM AUTHOR]