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Stomatal opening in plant leaves is regulated through a balance of carbon and water exchange under different environmental conditions. Accurate estimation of stomatal regulation is crucial for understanding how plants respond to changing environmental conditions, particularly under climate change. A new generation of optimality‐based modelling schemes determines instantaneous stomatal responses from a balance of trade‐offs between carbon gains and hydraulic costs, but most such schemes do not account for biochemical acclimation in response to drought. Here, we compare the performance of six instantaneous stomatal optimisation models with and without accounting for photosynthetic acclimation. Using experimental data from 37 plant species, we found that accounting for photosynthetic acclimation improves the prediction of carbon assimilation in a majority of the tested models. Photosynthetic acclimation contributed significantly to the reduction of photosynthesis under drought conditions in all tested models. Drought effects on photosynthesis could not accurately be explained by the hydraulic impairment functions embedded in the stomatal models alone, indicating that photosynthetic acclimation must be considered to improve estimates of carbon assimilation during drought. Summary statement: Accounting for photosynthetic acclimation improves the predictions of carbon assimilation in all the stomatal optimisation models evaluated. The influence of drought on photosynthesis cannot be fully explained by the hydraulic impairment function of the stomatal models alone. [ABSTRACT FROM AUTHOR]

Urban air pollution is a crucial global challenge, mainly originating from urbanization and industrial activities, which are continuously increasing. Vegetation serves as a natural air filter for air pollution, but adverse effects on plant health, photosynthesis, and metabolism can occur. Recent omics technologies have revolutionized the study of molecular plant responses to air pollution, overcoming previous limitations. This review synthesizes the latest advancements in molecular plant responses to major air pollutants, emphasizing ozone (O3), nitrogen oxides (NOX), and particulate matter (PM) research. These pollutants induce stress responses common to other abiotic and biotic stresses, including the activation of reactive oxygen species (ROSs)-scavenging enzymes and hormone signaling pathways. New evidence has shown the central role of antioxidant phenolic compound biosynthesis, via the phenylpropanoid pathway, in air pollution stress responses. Transcription factors like WRKY, AP2/ERF, and MYB, which connect hormone signaling to antioxidant biosynthesis, were also affected. To date, research has predominantly focused on laboratory studies analyzing individual pollutants. This review highlights the need for comprehensive field studies and the identification of molecular tolerance traits, which are crucial for the identification of tolerant plant species, aimed at the development of sustainable nature-based solutions (NBSs) to mitigate urban air pollution. [ABSTRACT FROM AUTHOR]

Invasive plant species are often characterized by superior resource acquisition capabilities compared with native species, contributing to their success in new environments. However, the dominance of these species varies, and not all invasive species become dominant, nor are all native species uniformly vulnerable to competitive exclusion. In this study, we analyzed 19 functional traits across 144 herbaceous plant species in Guangzhou, China. The studied species included 31 invasive dominant species (IDS), 19 invasive non-dominant species (INS), 63 native dominant species (NDS), and 31 native non-dominant species (NNS). Our findings reveal no significant differences in functional traits between IDS and INS, indicating a broad trait similarity within invasive categories. Pronounced similarities between invasive species and NDS suggest an ecological equivalency that facilitates successful integration and competition in new habitats. Notable differences in several key traits—height, leaf thickness, leaf water content, stoichiometry, photosynthetic rate, water use efficiency, and nitrogen use efficiency—indicate a competitive superiority in resource acquisition and utilization for invasive species over NNS. These distinctions are vital for understanding the mechanisms driving the success of invasive species and are crucial for developing strategies to manage their impact on native ecosystems. [ABSTRACT FROM AUTHOR]

The use of wood distillate (WD) is emerging as a valuable strategy for protecting horticultural crops from the oxidizing effects of ozone (O3). To fully understand its effectiveness, extensive testing on different plant species is needed. As a viable interim measure, an assessment of WD efficacy in model plants can be made until species-specific results become available. The aim of this study is to evaluate the ability of WD to protect the ozone-sensitive tobacco plant (Nicotiana tabacum L.) BelW3 from the oxidizing effects of O3, using the ozone-resistant tobacco plant BelB as a benchmark. The protective effect was evaluated during treatment applications and three weeks after these were completed. Ten BelW3 and five BelB plants were grown just outside Parma from June to October 2023, a period when average maximum O3 concentrations were at least 120 ppb. Starting from July, five BelW3 plants were sprayed weekly with WD at 0.2% for two months. Morphometric and photosynthetic measurements were then taken after six and 11 weeks from the beginning of treatments and three weeks after the end to assess protection persistence (if any). BelW3 showed a significant effect of O3 compared to BelB plants for both morphometric and photosynthetic measurements, exhibiting increased necrotic areas on the leaf blade, reduced number of viable leaves, reduced average plant height, together with reduced chlorophyll content and impaired photosynthetic system functionality. BelW3 plants also showed a significant decrease in the efficiency of parameters related to PSII and PSI when compared to BelB. Wood distillate application, however, successfully mitigated O3 effects on BelW3, as revealed by morphometric and photosynthetic values, which were in line with those observed in BelB. Notably, WD protective effect persisted 3 weeks after treatment cessation, highlighting the short-term protective capacity of the distillate against the oxidative action of O3. [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]

Abstract. Climate change is dramatically altering global precipitation patterns across terrestrial ecosystems, making it critically important that we understand both how and why plant species vary in their drought sensitivities. Andropogon gerardii and Schizachyrium scoparium , both C4 grasses, provide a model system for understanding the physiological mechanisms that determine how species of a single functional type can differ in drought responses, an issue remains a critical gap in our ability to model and predict the impacts of drought on grassland ecosystems. Despite its greater lability of foliar water content, previous experiments have demonstrated that S. scoparium maintains higher photosynthetic capacity during droughts. It is therefore likely that the ability of S. scoparium to withstand drought instead derives from a greater metabolic resistance to drought. Here, we tested the following hypotheses: (H1) A. gerardii is more vulnerable to drought than S. scoparium at both the population and organismal levels, (H2) A. gerardii is less stomatally flexible than S. scoparium , and (H3) A. gerardii is more metabolically limited than S. scoparium. Our results indicate that it is actually stomatal limitations of CO2 supply that limit A. gerardii photosynthesis during drought. Schizachyrium scoparium was more drought-resistant than A. gerardii based on long-term field data, organismal biomass production and physiological gas exchange measurements. While both S. scoparium and A. gerardii avoided metabolic limitation of photosynthesis, CO2 supply of A. gerardii was greatly reduced during late-stage drought stress. That two common, co-occurring C4 species possess such different responses to drought highlights the physiological variability inherent within plant functional groups and underscores the need for more studies of C4 drought tolerance. [ABSTRACT FROM AUTHOR]

Carbon dioxide is present in the Earth's atmosphere and it acts as a major contributor in greenhouse gases. Exposure to carbon dioxide can have devastating effects on a person's health. Green Biotechnology may contribute to the reduction of greenhouse gas emissions, in which plants play an important role as carbon sinks by sequestrating carbon through photosynthesis. Carbon sequestration refers to the long-term storage of carbon in plants, soils, geologic formations, and the ocean. Current work is focused on exploring carbon dioxide uptake by different methods of green biotechnology and how environmental pollution affects that uptake. The study examined how the relationship between environmental pollution and carbon sequestration can be optimized by the technique of green biotechnology which affects the overall plant health. For this purpose, leaves from twenty-six plant species including Michelia, Anona Squamosa, Catharantha roseus, Elaeis Guineenis, Hibiscus rosa sinensis, and Epipremnun pinnatum were taken and divided into two sets. One set was washed with water and the other one was left with dirt on it to demonstrate the effect of pollution on carbon sequestration. Leaves were placed in a transparent photosynthetic chamber equipped with CO2 and O2, and light biosensors. Chlorophyll concentration was determined using a spectrophotometer. Out of twenty-six different species of plants, Hibiscus rosa sinensis sequestered the least amount of CO2 among all the plants with 42 ppm while Anona Squamosa exhibited highest levels of CO2 sequestration with 1025 ppm. There is a correlation between carbon sequestration and chlorophyll content. Plants that show a substantial amount of carbon sequestrated also have a greater amount of chlorophyll that help in photosynthesis. Furthermore, it was found that the unpolluted leaves of Michelia removed 388 ppm CO2 from the environment while the polluted leaves removed only 145 ppm CO2. [ABSTRACT FROM AUTHOR]

This article examines the efficiency and diversity of photorespiration, a metabolic pathway in plants that has traditionally been seen as wasteful. The authors focus on the Brassicaceae family, which includes important crop species, and investigate the presence of C3-C4 intermediates, plants that use a photorespiratory shuttle to concentrate carbon. They find that C3-C4 intermediacy is rare but present in some members of the Brassicaceae family, and they analyze the metabolic variation within this family compared to their closest C4 relative. The study provides insights into the evolution and optimization of photosynthetic pathways in different plant species. Additionally, the article discusses the potential of C3-C4 intermediates to enhance climate resilience in the face of climate change. The authors conducted a study on 28 species of Brassicaceae, a plant family without C4 relatives, and discovered significant diversity in their photosynthetic characteristics. They found that C3-C4 intermediates can efficiently reclaim CO2 and improve water use efficiency in low CO2 conditions, making them more adaptable to climate variability and abiotic stress compared to other photosynthetic types. The authors propose that these findings could be utilized to ensure food production and enhance agricultural sustainability in the future. [Extracted from the article]

Urban air pollution is a crucial global challenge, mainly originating from urbanization and industrial activities, which are continuously increasing. Vegetation serves as a natural air filter for air pollution, but adverse effects on plant health, photosynthesis, and metabolism can occur. Recent omics technologies have revolutionized the study of molecular plant responses to air pollution, overcoming previous limitations. This review synthesizes the latest advancements in molecular plant responses to major air pollutants, emphasizing ozone (O3), nitrogen oxides (NOX), and particulate matter (PM) research. These pollutants induce stress responses common to other abiotic and biotic stresses, including the activation of reactive oxygen species (ROSs)-scavenging enzymes and hormone signaling pathways. New evidence has shown the central role of antioxidant phenolic compound biosynthesis, via the phenylpropanoid pathway, in air pollution stress responses. Transcription factors like WRKY, AP2/ERF, and MYB, which connect hormone signaling to antioxidant biosynthesis, were also affected. To date, research has predominantly focused on laboratory studies analyzing individual pollutants. This review highlights the need for comprehensive field studies and the identification of molecular tolerance traits, which are crucial for the identification of tolerant plant species, aimed at the development of sustainable nature-based solutions (NBSs) to mitigate urban air pollution.

Zinc (Zn) is a vital micronutrient for all living organisms, but in high concentrations, it is a major anthropogenic pollutant. In this study, it was investigated the effect of zinc excess concentrations (50, 100, and 150 mg kg−1) in the substrate on some physiological parameters and the dynamics of fatty acid (FA) content in yellow mustard (Sinapis alba L. cv. Belgia) and oriental mustard (Brassica juncea L. (Czern) cv. Slavanka). The Zn concentration of 50 mg kg−1 did not affect the physiological parameters of yellow mustard, whereas some physiological parameters slightly decreased in oriental mustard. Moreover, this concentration stimulated an increase in total and unsaturated FAs content in leaves of both species, along with high Zn accumulation by both species. The Zn concentrations of 100 and 150 mg kg−1 in substrate had a negative effect on the state of plants as measured by the studied physiological parameters and caused different changes in FAs content in yellow and oriental mustard. Particularly, the total amount of FA increased in comparison to the control, but this increase was due to an elevation in saturated FA (SFA) content. At the same time, the total FA content in oriental mustard slightly decreased while the proportion of unsaturated FAs to SFA kept rising. According to the present data and analysis of the available literature, two strategies of adaptation to heavy metals were suggested through the changes in FAs: height-resistant horticultural plant species on the one side and sensitive species on the other. [ABSTRACT FROM AUTHOR]

While increased foliar photosynthesis is well documented across many plant species in response to diverse modes of herbivory, the compensatory ability of photosynthetically active reproductive structures is unknown. To address this, we partially defoliated basal florets in seed heads of crested wheatgrass (Agropyron cristatum (L.) Gaertn.), an exotic Eurasian perennial bunchgrass widely distributed across North American sagebrush steppe. We followed direct and indirect responses by tracking post-clipping photosynthesis in clipped basal and unclipped distal florets, respectively, and comparing these to similar florets on unclipped seed heads. Compensatory photosynthesis was apparent 24 h after clipping; over the pre-anthesis period, clipped basal floret photosynthesis was + 62%, stomatal conductance was + 82%, and PSII photochemical yield was − 39% of unclipped controls. After anthesis, intact florets distal to clipped florets had modestly higher photosynthetic rates compared to controls, while basal floret rates did not differ between treatments. Compensatory photosynthesis reduced intrinsic water use efficiency (iWUE; photosynthesis/stomatal conductance) 68–40% below controls over pre- and post-anthesis periods, respectively. Specific mass (dry mass/area) of clipped florets was − 15% of controls, while florets distal to these had specific mass 11% greater than distal or basal florets on unclipped seed heads. These results suggest damaged basal florets provided carbon to unaffected distal florets. This could explain crested wheatgrass's ability to produce viable seeds under conditions limiting to native bunchgrasses, and presents a novel mechanism germane to the development of convergent drought- and grazing-tolerance traits important to arid and semi-arid rangeland plant community resilience to climate variability. [ABSTRACT FROM AUTHOR]

In many plant species, expression of the nuclear encoded Rubisco small subunit (SSu) varies with environmental changes, but the functional role of any changes in expression remains unclear. In this study, we investigated the impact of differential expression of Rubisco SSu isoforms on carbon assimilation in Arabidopsis. Using plants grown at contrasting temperatures (10 °C and 30 °C), we confirm the previously reported temperature response of the four RbcS genes and extend this to protein expression, finding that warm-grown plants produce Rubisco containing ~65% SSu-B and cold-grown plants produce Rubisco with ~65% SSu-A as a proportion of the total pool of subunits. We find that these changes in isoform concentration are associated with kinetic changes to Rubisco in vitro : warm-grown plants produce a Rubisco having greater CO2 affinity (i.e. higher S C/O and lower K C) but lower k catCO 2 at warm measurement temperatures. Although warm-grown plants produce 38% less Rubisco than cold-grown plants on a leaf area basis, warm-grown plants can maintain similar rates of photosynthesis to cold-grown plants at ambient CO2 and 30 °C, indicating that the carboxylation capacity of warm-grown Rubisco is enhanced at warmer measurement temperatures, and is able to compensate for the lower Rubisco content in warm-grown plants. This association between SSu isoform expression and maintenance of Rubisco activity at high temperature suggests that SSu isoform expression could impact the temperature response of C3 photosynthesis. [ABSTRACT FROM AUTHOR]

Light-harvesting chlorophyll a/b-binding (LHC) superfamily proteins play a vital role in photosynthesis. Although the physiological and biochemical functions of LHC genes have been well-characterized, the structural evolution and functional differentiation of the products need to be further studied. In this paper, we report the genome-wide identification and phylogenetic analysis of LHC genes in photosynthetic organisms. A total of 1222 non-redundant members of the LHC family were identified from 42 species. According to the phylogenetic clustering of their homologues with Arabidopsis thaliana, they can be divided into four subfamilies. In the subsequent evolution of land plants, a whole-genome replication (WGD) event was the driving force for the evolution and expansion of the LHC superfamily, with its copy numbers rapidly increasing in angiosperms. The selection pressure of photosystem II sub-unit S (PsbS) and ferrochelatase (FCII) families were higher than other subfamilies. In addition, the transcriptional expression profiles of LHC gene family members in different tissues and their expression patterns under exogenous abiotic stress conditions significantly differed, and the LHC genes are highly expressed in mature leaves, which is consistent with the conclusion that LHC is mainly involved in the capture and transmission of light energy in photosynthesis. According to the expression pattern and copy number of LHC genes in land plants, we propose different evolutionary trajectories in this gene family. This study provides a basis for understanding the molecular evolutionary characteristics and evolution patterns of plant LHCs. [ABSTRACT FROM AUTHOR]

Two main leaf types are recognized among vascular plant species: compound and simple. Compound leaves are believed to be photosynthetically more productive than simple ones, by diluting mass tissue in more projected area. Conversely, simple leaves are believed to be more stress-tolerant by packing mass tissue in less projected area during stress like drought. Nevertheless, convective cooling is more efficient in compound than simple leaves, a process that could alleviate water loss in drought periods. In Central Chile, woody species with simple and compound leaves coexist. This zone is facing a mega-drought event, causing browning and tree mortality. However, how severe droughts affect photosynthetic traits on both leaf-type species have not been addressed so far. We measured photosynthetic traits in well-watered and drought conditions in three compound and three simple leaf species, and drought response ratios were obtained. We hypothesized that with no water limitation compound leaf species will show higher net photosynthesis (AN) than simple leaf species associated with a higher mesophyll conductance (gm). Opposite results are expected for simple leaf species due to their stress-tolerant physiology, showing fewer changes in their photosynthetic traits. We found that gm and AN were larger in compound leaf species in well-watered conditions. With drought, both leaf-type species were negatively affected despite foliar temperature in compound leaf species was 4 °C lower. Our result suggests that regardless of leaf shape the matorral species in Central Chile will be seriously affected in their AN due to the megadrought currently affecting this zone. [ABSTRACT FROM AUTHOR]

The photosynthetic apparatus is a major reactive oxygen species (ROS) proliferator, especially in high-light environments. The role of ROS in photoinhibition and photoacclimation mechanisms has been extensively explored, primarily in model plant species. However, little work has been performed on the topic in non-Archaeplastida organisms, such as the model heterokont species Nannochloropsis oceanica. To investigate the photoacclimation and damaging impact of singlet oxygen and superoxide anions on the photosynthetic apparatus of N. oceanica, we subjected cells to two doses of methyl viologen and rose bengal. Significant findings: Rose bengal (a singlet-oxygen photosensitizer) induced changes to the photosynthetic apparatus and PSII photochemistry mirroring high-light-acclimated cells, suggesting that singlet-oxygen signaling plays a role in the high-light acclimation of PSII. We further suggest that this singlet-oxygen pathway is mediated outside the plastid, given that rose bengal caused no detectable damage to the photosynthetic apparatus. Methyl viologen (a superoxide-anion sensitizer) induced an enhanced non-photochemical quenching response, similar to what occurs in high-light-acclimated cells. We propose that superoxide anions produced inside the plastid help regulate the high-light acclimation of photoprotective pathways. [ABSTRACT FROM AUTHOR]

Aims: Vegetation in ironstone outcrops is under potential environmental stressors. The aim of this work was to understand the relationships between the ecological strategies of species from ironstone outcrops in Brazil and their photosynthetic adjustments, and to contribute for the selection of species for the recovery of mined environments. Methods: A total of 22 species belonging to 12 families were selected over canga vegetation. The physiological characteristics, chlorophyll a fluorescence and chlorophyll indices, were evaluated during the rainy and dry seasons. Analysis of competitor, stress-tolerator and ruderal (CSR) ecological strategies was performed during the rainy season for each species using functional leaf characteristics. Results: The species presented the following ecological strategies: tolerance to stress (74.76%), competition (22.31%) and ruderality (2.93%). Despite a weak correlation between the ecological stress-tolerant strategy and photosynthetic variables, the low soil fertility and reduced rainfall during the dry season led to photochemical adjustments. The species were divided into five distinct groups based on the ability to use and dissipate excess light energy. Some species showed maintenance or increments in photochemical efficiency parameters, chlorophyll indices, and the capacity to avoid damage to the photosynthetic complex through a photoprotective process during the dry season. Conclusions: The photochemical responses observed highlighted the diversity of adaptive strategies found in plant species from ironstone outcrops. The different photosynthetic adjustments are related to the competition capacity and stress tolerance mechanisms. Thus, the analyzed physiological parameters can be used for selecting plant species for the recovery of environments impacted by mining companies. [ABSTRACT FROM AUTHOR]

The relationships of ornamental plants with soil microorganisms, which can either stimulate or suppress their performance and thereby impact the production process, remain largely unexplored. Therefore, we conducted a study on 10 common ornamental plant species available in large DIY stores to compare the microbiological and physicochemical properties of substrata used for their cultivation and assess their colonisation by root-inhabiting fungi, namely arbuscular mycorrhizal fungi (AMF), dark septate endophytes (DSE), and Olpidium spp. The substrata exhibited significant variations in their microbiological and physicochemical properties, depending on both their origin from DIY stores and the ornamental plant species. Hyphae and spores of AMF were not found in any analysed roots and substrata, respectively, except for the low level of colonisation observed in Echinacea purpurea roots. However, 8 plant species were colonised by DSE and 8 by Olpidium spp. More acidic substrata with a high content of organic matter and the ability to hold water favoured the colonisation of Olpidium spp. in roots, and the opposite trend was found for DSE. The occurrence of both groups of endophytes, especially Olpidium spp., was limited in plants with higher biomass and vitality. In conclusion, commercially available ornamental plant species rarely form symbiotic associations with AMF in pot cultivation. Instead, they are often colonised by other root-inhabiting fungi, such as DSE, which are known to have either positive or negative effects on their hosts, and Olpidium spp., which can transfer plant viruses. Such results are most likely due to the high nutrient, organic matter, and water contents in the substrata. • Substrata varied greatly in microbiological and physicochemical properties. • Spores of AMF were not found in any of the studied substrata. • Low AMF colonisation was observed in roots of only one ornamental plant. • High frequency of DSE and Olpidium occurrence was found in ornamental plants. • Low pH, high organic matter content and WHC favoured Olpidium occurrence. [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]

Background: Hydrangea macrophylla var. Maculata 'Yinbianxiuqiu' (YB) is an excellent plant species with beautiful flowers and leaves with silvery white edges. However, there are few reports on its leaf color characteristics and color formation mechanism. Results: The present study compared the phenotypic, physiological and transcriptomic differences between YB and a full-green leaf mutant (YM) obtained from YB. The results showed that YB and YM had similar genetic backgrounds, but photosynthesis was reduced in YB. The contents of pigments were significantly decreased at the edges of YB leaves compared to YM leaves. The ultrastructure of chloroplasts in the YB leaves was irregular. Transcriptome profiling identified 7,023 differentially expressed genes between YB and YM. The expression levels of genes involved in photosynthesis, chloroplast development and division were different between YB and YM. Quantitative real-time PCR showed that the expression trends were generally consistent with the transcriptome data. Conclusions: Taken together, the formation of the silvery white leaf color of H. macrophylla var. maculata was primarily due to the abnormal development of chloroplasts. This study facilitates the molecular function analysis of key genes involved in chloroplast development and provides new insights into the molecular mechanisms involved in leaf coloration in H. macrophylla. [ABSTRACT FROM AUTHOR]

Photosynthesis is a process highly sensitive to various abiotic and biotic stresses in plants. Among them, the major abiotic stress, waterlogging, affects the crop's growth and productivity. Under waterlogging, the photosynthetic apparatus of plants was destroyed. Waterlogging reduced chlorophyll content and the net photosynthetic rate. Therefore, this updated review summarized the effect of waterlogging on chloroplast ultrastructure, photosynthetic characteristics, and chlorophyll fluorescence attributes of plant species. By studying various research papers, we found that intercellular concentration of available carbon dioxide in mesophyll cells, assimilation of carbon, and the net photosynthetic ratio declined under waterlogging. The chlorophyll fluorescence efficiency of plants decreased under waterlogging. Thus, the study of photosynthesis in plants under waterlogging should be done with respect to changing climate. Moreover, the recognition of photosynthetic characteristics present in tolerant species will be beneficial for designing the waterlogging-tolerant crop plant in changing environments. [ABSTRACT FROM AUTHOR]

The diversity of functional traits still has not been studied enough in model plant species, even less so in little-known species. This experiment was carried out under the extreme heat of Sonoran Desert, using shading nets and under conditions where the availability of water and nutrients was not a stress factor. We evaluated how the low, intermediate and high sunlight regimes impact survival and promote multiple alterations on phenological and ecophysiological response of cultivated Capsicum annuum var. glabriusculum plants. Extremely warm temperatures promoted a high heat sum in degrees days throughout plants development. Most plants grown in high sunlight regimes did not survive; under intermediate sunlight regimes survival was high and plants developed vegetative and reproductively; but under low sunlight regimes plants survival was high; however, they developed just vegetatively. Photosynthetic response to light suggests that plants are physiologically acclimated to low and intermediate irradiance, whereas the CO2 assimilation curves suggest contrasting photosynthetic capacity traits. Under the intermediate sunlight regimes, plants strengthened their performance through multiple functional traits (e.g. CO2 and water diffusion traits, photosynthetic capacity, respiration, among others). Consequently, their biomass gain was faster and proportionally higher by 76 % with an investment of 14 % in fruits development. The principal components analysis extracted the main explanatory functional traits: photosynthetic nitrogen allocation, stomatal limitation, mesophyll conductance, Rubisco maximum carboxylation velocity, among others. In conclusion, phenological response and multiple functional traits determine plants acclimation to sunlight regimes and extremely warm temperatures in short term. [ABSTRACT FROM AUTHOR]

Projected rises in atmospheric CO2 concentration and minimum night-time temperatures may have important effects on plant carbon metabolism altering the carbon balance of the only two vascular plant species in the Antarctic Peninsula. We assessed the effect of nocturnal warming (8/5 °C vs. 8/8 °C day/night) and CO2 concentrations (400 ppm and 750 ppm) on gas exchange, non-structural carbohydrates, two respiratory-related enzymes, and mitochondrial size and number in two species of vascular plants. In Colobanthus quitensis, light-saturated photosynthesis measured at 400 ppm was reduced when plants were grown in the elevated CO2 or in the nocturnal warming treatments. Growth in elevated CO2 reduced stomatal conductance but nocturnal warming did not. The short-term sensitivity of respiration, relative protein abundance, and mitochondrial traits were not responsive to either treatment in this species. Moreover, some acclimation to nocturnal warming at ambient CO2 was observed. Altogether, these responses in C. quitensis led to an increase in the respiration-assimilation ratio in plants grown in elevated CO2. The response of Deschampsia antarctica to the experimental treatments was quite distinct. Photosynthesis was not affected by either treatment; however, respiration acclimated to temperature in the elevated CO2 treatment. The observed short-term changes in thermal sensitivity indicate type I acclimation of respiration. Growth in elevated CO2 and nocturnal warming resulted in a reduction in mitochondrial numbers and an increase in mitochondrial size in D. antarctica. Overall, our results suggest that with climate change D. antarctica could be more successful than C. quitensis, due to its ability to make metabolic adjustments to maintain its carbon balance. [ABSTRACT FROM AUTHOR]

Photosynthesis is a process that indicates the productivity of crops. The estimation of this variable can be achieved through methods based on mathematical models. Mathematical models are usually classified as empirical, mechanistic, and hybrid. To mathematically model photosynthesis, it is essential to know: the input/output variables and their units; the modeling to be used based on its classification (empirical, mechanistic, or hybrid); existing measurement methods and their invasiveness; the validation shapes and the plant species required for experimentation. Until now, a collection of such information in a single reference has not been found in the literature, so the objective of this manuscript is to analyze the most relevant mathematical models for the photosynthesis estimation and discuss their formulation, complexity, validation, number of samples, units of the input/output variables, and invasiveness in the estimation method. According to the state of the art reviewed here, 67% of the photosynthesis measurement models are mechanistic, 13% are empirical and 20% hybrid. These models estimate gross photosynthesis, net photosynthesis, photosynthesis rate, biomass, or carbon assimilation. Therefore, this review provides an update on the state of research and mathematical modeling of photosynthesis. [ABSTRACT FROM AUTHOR]

The boron (B) deficiency tolerance capacity of two grape materials, 'Xishui-4' (Vitis flexuosa) and 'Crystal' (V. vinifera × V. labrusca), were evaluated using a potted experiment in order to identify the B-use efficiency of grape and screen B-efficient grape resources. The sterile lines of two genotypes of grape were used as test materials, and a large number of test-tube seedlings were obtained through rapid propagation. The test-tube seedlings were acclimatization and transplanted, and the tested seedlings were treated with B stress after survival. In this experiment, the materials were cultured in nutrient solution, which contained 0.00 (B0), 0.25 (B1), and 0.50 (control) mg·L−1 B concentrations, and the two genotypes of grape seedlings were cultured in vitro. The results were counted after 60 days of culture. The results showed that the B deficiency significantly reduced the growth parameters such as plant height, leaf area, total root length, and dry biomass of the two genotypes, and the inhibition of 'Crystal' growth parameters was greater than that of 'Xishui-4'. Moreover, the B deficiency also affected photosynthesis of the two genotypes, such as decreased leaf photosynthetic pigments, net photosynthesis rate, transpiration rate, stomatal conductance, intercellular carbon dioxide concentration, and stomatal density. Interestingly, the decrease ranges of 'Crystal' were greater than those of 'Xishui-4', indicating that 'Crystal' photosynthesis was more susceptible to B deficiency. Under the control condition, the concentration and accumulation of B in 'Crystal' were significantly higher than those in 'Xishui-4'. However, under the condition of B deficiency, the B concentration, accumulation amount, accumulation rate, utilization index, and tolerance index of 'Xishui-4' were higher than those of 'Crystal', and the B transport capacity of 'Xishui-4' was more stable, indicating that 'Xishui-4' had a better tolerance against B-deficient stress than 'Crystal' did. Therefore, 'Xishui-4' is a plant with strong adaptability to B deficiency stress, which can be used as B efficient grape resources and a genetic improvement of B efficient grape. [ABSTRACT FROM AUTHOR]

The use of auxin mimics herbicides in agriculture is widespread in a great diversity of crops. The indiscriminate use of herbicides can cause adverse effects in the plants. Among the plant species that stand out for being highly competitive and resistant to biotic and abiotic stresses, it is the brazilian peppertree (Schinus terebinthifolius Raddi.). The objective of this work was to evaluate the phytotoxic and photosynthetic alteration effects of different rates simulating the drift of the herbicides 2,4-D and Dicamba in brazilian peppertree seedlings. The experiment was carried out in a completely randomized design with four replications. The treatments were arranged in 2 x 8 factorial design (herbicide x doses). The factor herbicide consisted the herbicides 2,4-D and Dicamba, and, the factor doses eight percentages of the herbicide applied. Phytotoxicity and alteration of photosynthetic and fluorescence of chlorophyll a parameters were evaluated. Increased rate of the 2,4-D and Dicamba cause phytotoxicity to the plants, whose Dicamba promotes greater injuries. Dicamba was the herbicide that caused the greatest damage to the photosynthetic apparatus on brazilian peppertree plants, while for 2,4-D the plants showed higher recovery potential after herbicidal exposure. [ABSTRACT FROM AUTHOR]

Photosynthetic characteristics are widely used as indicators of plant responses to global environmental changes such as precipitation change and nitrogen (N) deposition increase. How different plant species respond physiologically to the future precipitation change combined with increasing N availability is largely unclear. A field experiment was conducted to study responses in seasonal and interannual leaf carbon (C) exchange of two dominant plant species, Leymus chinensis and Stipa grandis , to additional water (either as spring snow or as summer water) and N application in a semi-arid temperate steppe of China. Our results showed that spring snow and summer water addition both increased the maximum photosynthetic rate (Amax) of two dominant species. Such effect was likely caused by raised light saturation point, the maximum apparent quantum yield, stomatal conductance, and transpiration rate. The N application combined with spring snow or summer water addition both enhanced Amax of S. grandis in both experimental years, whereas N application only increased Amax of L. chinensis combined with summer water addition. Their responses were attributed to a concurrent increase in leaf N concentration (Nleaf) and decrease in leaf phosphorus (P) concentration (Pleaf), indicating that Nleaf and Pleaf affect photosynthetic characteristics to regulate leaf C exchange. Our results suggest that differentiated responses among different species in photosynthetic characteristics may lead to changes in ecosystem structure and functioning under increasing precipitation and N deposition. [ABSTRACT FROM AUTHOR]

Overcompensation to herbivory is prevalent among plant species. However, we do not yet fully understand why plant species vary in their compensatory abilities. It is highly likely that overcompensation is determined by the ability of plants to elevate photosynthesis in response to herbivory, which is dictated by evolutionary exposure to grazing. Here, we tested the hypothesis that photosynthetic overcompensation should be predictable based on plant life form by simulating herbivore damage on four plant species: two common range grasses with long evolutionary exposure to grazing (Andropogon gerardii, Bouteloua curtipendula) and two common understory forbs that are resistant to, and therefore experience little, grazing (Alliaria petiolata, Symplocarpus foetidus). We measured leaf-level gas exchange in a high-resolution time series that extended throughout the growing season. We found no evidence of photosynthetic compensation for three of the four plant species. Interestingly, only A. petiolata, a highly invasive species, demonstrated increased photosynthesis and stomatal conductance following clipping. Further, the effects were short-lived, as both photosynthesis and stomatal conductance returned to baseline levels within 24 h. Our results suggest that elevated photosynthesis to herbivory might not be a general mechanism by which plants either resist or tolerate herbivory. [ABSTRACT FROM AUTHOR]

Copyright of Agricultural Research in the Tropics / Pesquisa Agropecuária Tropical is the property of Pesquisa Agropecuaria Tropical and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

What causes variation in species abundance for a given site remains a central question in community ecology. Foundational to trait-based ecology is the expectation that functional traits determine species abundance. However, the relative success of using functional traits to predict relative abundance is questionable. One reason is that the diversity in plant function is greater than that characterized by the few most commonly and easily measurable traits. Here, we measured 10 functional traits and the stem density of 101 woody plant species in a 200,000 m2 permanent, mature, subtropical forest plot (high precipitation and high nitrogen, but generally light- and phosphorus-limited) in southern China to determine how well relative species abundance could be predicted by functional traits. We found that: (1) leaf phosphorus content, specific leaf area, maximum CO2 assimilation rate, maximum stomata conductance, and stem hydraulic conductivity were significantly and negatively associated with species abundance, (2) the ratio of leaf nitrogen content to leaf phosphorus content (N:P) and wood density were significantly positively correlated with species abundance; (3) neither leaf nitrogen content nor leaf turgor loss point were related to species abundance; (4) a combination of N:P and maximum stomata conductance accounted for 44% of the variation in species' abundances. Taken together, our findings suggested that the combination of these functional traits are powerful predictors of species abundance. Species with a resource-conservative strategy that invest more in their tissues are dominant in the mature, subtropical, evergreen forest. [ABSTRACT FROM AUTHOR]

SUMMARY: Photosynthetic inefficiencies limit the productivity and sustainability of crop production and the resilience of agriculture to future societal and environmental challenges. Rubisco is a key target for improvement as it plays a central role in carbon fixation during photosynthesis and is remarkably inefficient. Introduction of mutations to the chloroplast‐encoded Rubisco large subunit rbcL is of particular interest for improving the catalytic activity and efficiency of the enzyme. However, manipulation of rbcL is hampered by its location in the plastome, with many species recalcitrant to plastome transformation, and by the plastid's efficient repair system, which can prevent effective maintenance of mutations introduced with homologous recombination. Here we present a system where the introduction of a number of silent mutations into rbcL within the model plant Nicotiana tabacum facilitates simplified screening via additional restriction enzyme sites. This system was used to successfully generate a range of transplastomic lines from wild‐type N. tabacum with stable point mutations within rbcL in 40% of the transformants, allowing assessment of the effect of these mutations on Rubisco assembly and activity. With further optimization the approach offers a viable way forward for mutagenic testing of Rubisco function in planta within tobacco and modification of rbcL in other crops where chloroplast transformation is feasible. The transformation strategy could also be applied to introduce point mutations in other chloroplast‐encoded genes. Significance Statement: A simplified transformation strategy was developed to perform site‐directed mutagenesis in the chloroplast‐encoded Rubisco large subunit of tobacco. This approach reduces unwanted mismatch repair events, enables rapid screening of transformed lines that possess desired mutations and can be applied to modify any chloroplast‐encoded gene in plant species amenable to plastid genome transformation. [ABSTRACT FROM AUTHOR]

Premise: The distribution and even the survival of plant species are influenced by temperature. In an old climatically buffered infertile landscape (OCBIL) in Brazil, we previously characterized different strategies for foliar water uptake (FWU). It is possible that photosystem II tolerance to heat and excessive light intensity varies among species with different FWU capacities. Methods: The relationship between FWU, photoinhibition, and thermotolerance was investigated in seven species from this ecosystem. Results: The species with slow water absorption and high water absorption are those that presented less photoinhibition. Contrastingly, the species that have fast and low water absorption presented greater thermotolerance when their leaves are totally hydrated. However, when there is greater leaf dehydration, the most thermotolerant species were those with slow but high water absorption. Conclusions: Foliar water uptake is an important trait for plants to tolerate excessive light intensity and higher temperatures. Plants in this OCBIL may be differentially affected by future global warming, and the best strategy to deal with this expected climate change is with slow and high absorption of water. [ABSTRACT FROM AUTHOR]

The photosynthetic pathway of plants is a fundamental trait that influences terrestrial environments from the local to global level. The distribution of different photosynthetic pathways in Australia is expected to undergo a substantial shift due to climate change and rising atmospheric CO2; however, tracking change is hindered by a lack of data on the pathways of species, as well as their distribution and relative cover within plant communities. Here we present the photosynthetic pathways for 2428 species recorded across 541 plots surveyed by Australia's Terrestrial Ecosystem Research Network (TERN) between 2011 and 2017. This dataset was created to facilitate research exploring trends in vegetation change across Australia. Species were assigned a photosynthetic pathway using published literature and stable carbon isotope analysis of bulk tissue. The photosynthetic pathway of species can be extracted from the dataset individually, or used in conjunction with vegetation surveys to study the occurrence and abundance of pathways across the continent. This dataset will be updated as TERN's plot network expands and new information becomes available. Measurement(s) oxidative photosynthetic carbon pathway Technology Type(s) digital curation • elemental analysis isotope ratio mass spectrometry Factor Type(s) date • geographic location Sample Characteristic - Organism Viridiplantae Sample Characteristic - Environment terrestrial natural environment Sample Characteristic - Location Australia Machine-accessible metadata file describing the reported data: https://doi.org/10.6084/m9.figshare.14134994 [ABSTRACT FROM AUTHOR]

The study estimates the parameters of the photosynthesis–irradiance relationship (PN/I) of a sedge-grass marsh (Czech Republic, Europe), represented as an active "green" surface—a hypothetical "big-leaf". Photosynthetic parameters of the "big-leaf" are based on in situ measurements of the leaf PN/I curves of the dominant plant species. The non-rectangular hyperbola was selected as the best model for fitting the PN/I relationships. The plant species had different parameters of this relationship. The highest light-saturated rate of photosynthesis (Asat) was recorded for Glyceria maxima and Acorus calamus followed by Carex acuta and Phalaris arundinacea. The lowest Asat was recorded for Calamagrostis canescens. The parameters of the PN/I relationship were calculated also for different growth periods. The highest Asat was calculated for the spring period followed by the summer and autumn periods. The effect of the species composition of the local plant community on the photosynthetic parameters of the "big-leaf" was addressed by introducing both real (recorded) and hypothetical species compositions corresponding to "wet" and "dry" hydrological conditions. We can conclude that the species composition (or diversity) is essential for reaching a high Asat of the "big-leaf "representing the sedge-grass marsh in different growth periods. [ABSTRACT FROM AUTHOR]

Differentiation in physiological activity is a critical component of resource partitioning in resource-limited environments. For example, it is crucial to understand how plant physiological performance varies through time for different functional groups to forecast how terrestrial ecosystems will respond to change. Here, we tracked the seasonal progress of 13 plant species representing C3 shrub, perennial C3 and C4 grass, and annual forb functional groups of the Colorado Plateau, USA. We tested for differences in carbon assimilation strategies and how photosynthetic rates related to recent, seasonal, and annual precipitation and temperature variables. Despite seasonal shifts in species presence and activity, we found small differences in seasonally weighted annual photosynthetic rates among groups. However, differences in the timing of maximum assimilation (Anet) were strongly functional group-dependent. C3 shrubs employed a relatively consistent, low carbon capture strategy and maintained activity year-round but switched to a rapid growth strategy in response to recent climate conditions. In contrast, grasses maintained higher carbon capture during spring months when all perennials had maximum photosynthetic rates, but grasses were dormant during months when shrubs remained active. Perennial grass Anet rates were explained in part by precipitation accumulated during the preceding year and average maximum temperatures during the past 48 h, a result opposite to shrubs. These results lend insight into diverse physiological strategies and their connections to climate, and also point to the potential for shrubs to increase in abundance in response to increased climatic variability in drylands, given shrubs' ability to respond rapidly to changing conditions. [ABSTRACT FROM AUTHOR]

A close correlation between stomatal conductance and the steady‐state photosynthetic rate has been observed for diverse plant species under various environmental conditions. However, it remains unclear whether stomatal conductance is a major limiting factor for the photosynthetic rate under naturally fluctuating light conditions. We analysed a SLAC1 knockout rice line to examine the role of stomatal conductance in photosynthetic responses to fluctuating light. SLAC1 encodes a stomatal anion channel that regulates stomatal closure. Long exposures to weak light before treatments with strong light increased the photosynthetic induction time required for plants to reach a steady‐state photosynthetic rate and also induced stomatal limitation of photosynthesis by restricting the diffusion of CO2 into leaves. The slac1 mutant exhibited a significantly higher rate of stomatal opening after an increase in irradiance than wild‐type plants, leading to a higher rate of photosynthetic induction. Under natural conditions, in which irradiance levels are highly variable, the stomata of the slac1 mutant remained open to ensure efficient photosynthetic reaction. These observations reveal that stomatal conductance is important for regulating photosynthesis in rice plants in the natural environment with fluctuating light. A close correlation between stomatal conductance and the steady‐state photosynthetic rate has been observed for diverse plant species under various environmental conditions. However, it remains unclear whether stomatal conductance is a major limiting factor for the photosynthetic rate under naturally fluctuating light conditions. The present study showed that stomatal conductance is an important limiting factor for photosynthesis under fluctuating light conditions and that greater stomatal conductance contributed to higher photosynthetic rates in naturally fluctuating light conditions. [ABSTRACT FROM AUTHOR]

Variations of photosynthetic structures in different tissues or cells are in coordination with changes in various aspects, e.g. physiology, biochemistry, gene expression, etc. Most C4 plant species undergo developmental enhancement of the photosynthetic system, which may present different modes of changes between anatomy and physiology/biochemistry. In the current study, we investigated a Kranz-type C4 species Salsola ferganica with the progressive development of photosynthetic (PS) structure, performance of PS physiology, induction of PS enzymes, and transcriptional and translational regulation of PS genes, results revealed that S. ferganica presented C3 type anatomy in cotyledons but C4 type in leaves (C3/L4), with the C4 system separation of initial carbon fixation in the palisade mesophyll (M) cells and the following incorporation into triosephosphates and sugars in the bundle sheath (BS) cells, respectively. The BS cells continuously surrounded the vascular bundles and water storage cells in leaf anatomic structure. Compared to the single-cell C4 species Suaeda aralocaspica , S. ferganica exhibited similar developmental enhancement of C4 syndrome temporally and spatially in anatomic structures, enzyme activities, and gene expression, which suggests that completion of differentiation of the photosynthetic system is necessary for a C4 assimilation pathway. Besides, S. ferganica also displayed some different characteristics compared to S. aralocaspica in photosynthetic physiology, e.g. a more flexible δ13C value, much lower phosphoenolpyruvate carboxylase (PEPC) activity, and an insensitive response to stimuli, etc., which were not typical C4 characteristics. We speculate that this may suggest a different status of these two species in the evolutionary process of the photosynthesis pathway. Our findings will contribute to further understanding of the diversity of photosynthesis systems in Kranz-type C4 species and the Salsola genus. [ABSTRACT FROM AUTHOR]

Plant structural and biochemical traits are frequently used to characterise the life history of plants. Although some common patterns of trait covariation have been identified, recent studies suggest these patterns of covariation may differ with growing location and/or plant functional type (PFT). Mediterranean forest tree/shrub species are often divided into three PFTs based on their leaf habit and form, being classified as either needleleaf evergreen (Ne), broadleaf evergreen (Be), or broadleaf deciduous (Bd). Working across 61 mountainous Mediterranean forest sites of contrasting climate and soil type, we sampled and analysed 626 individuals in order to evaluate differences in key foliage trait covariation as modulated by growing conditions both within and between the Ne , Be , and Bd functional types. We found significant differences between PFTs for most traits. When considered across PFTs and by ignoring intraspecific variation, three independent functional dimensions supporting the Leaf-Height-Seed framework were identified. Some traits illustrated a common scaling relationship across and within PFTs, but others scaled differently when considered across PFTs or even within PFTs. For most traits much of the observed variation was attributable to PFT identity and not to growing location, although for some traits there was a strong environmental component and considerable intraspecific and residual variation. Nevertheless, environmental conditions as related to water availability during the dry season and to a smaller extend to soil nutrient status and soil texture, clearly influenced trait values. When compared across species, about half of the trait-environment relationships were species-specific. Our study highlights the importance of the ecological scale within which trait covariation is considered and suggests that at regional to local scales, common trait-by-trait scaling relationships should be treated with caution. PFT definitions by themselves can potentially be an important predictor variable when inferring one trait from another. These findings have important implications for local scale dynamic vegetation models. [ABSTRACT FROM AUTHOR]

The plant economics spectrum is increasingly recognized as a major determinant of plant species effects on terrestrial ecosystem functioning related to carbon cycling. However, the role of plant economic strategies in the effects of living root activity on soil organic carbon (SOC) dynamics through rhizodeposition remains unexplored, despite SOC being the largest terrestrial carbon pool.Using a continuous 13C‐labelling method allowing partitioning of plant and soil sources to carbon fluxes and pools, we studied here the linkages between plant economic strategies and SOC cycling processes in a 'common garden' greenhouse experiment. It includes a panel of 12 grassland species selected along a gradient of economic traits and belonging to three functionnal groups (C3 grasses, forbs and legumes).All species induced an acceleration of native SOC mineralization but this rhizosphere priming effect (RPE) substantially differed across species and varied eleven‐fold by the end of the experiment (from +26% to +295% relative to unplanted soil). Interspecific variation in RPE was primarily linked to plant photosynthetic activity associated to species economic strategies of light and CO2 resource acquisition and processing. Fast‐growing acquisitive species, such as legumes, featured large RPE, in relation with their high canopy photosynthesis coupled to high leaf photosynthetic capacity and large net primary productivity allocated above‐ground. This large RPE was further associated with high root metabolic activity, rhizodeposition and soil microbial activity. In contrast, fine‐root growth and economic traits related to soil resource foraging ability were poor predictors of RPE.The formation of new root‐derived SOC varied nine‐fold across species and was similarly positively related to the net primary productivity allocated above‐ground. Fast‐growing acquisitive species with a high photosynthetic activity induced a disproportionately large RPE relative to SOC formation.Synthesis. Overall, our study demonstrates that rhizodeposition is a major mechanism through which plant economic strategies of grassland species control soil carbon dynamics. Acquisitive versus conservative species were associated with high versus low rates of photosynthesis and rhizodeposition, in turn leading to fast versus slow SOC turnover. This emphasizes the importance of considering rhizosphere processes for understanding plant species effects on soil biogeochemistry. [ABSTRACT FROM AUTHOR]

Summary: In this work, we review the physiological and molecular mechanisms that allow vascular plants to perform photosynthesis in extreme environments, such as deserts, polar and alpine ecosystems. Specifically, we discuss the morpho/anatomical, photochemical and metabolic adaptive processes that enable a positive carbon balance in photosynthetic tissues under extreme temperatures and/or severe water‐limiting conditions in C3 species. Nevertheless, only a few studies have described the in situ functioning of photoprotection in plants from extreme environments, given the intrinsic difficulties of fieldwork in remote places. However, they cover a substantial geographical and functional range, which allowed us to describe some general trends. In general, photoprotection relies on the same mechanisms as those operating in the remaining plant species, ranging from enhanced morphological photoprotection to increased scavenging of oxidative products such as reactive oxygen species. Much less information is available about the main physiological and biochemical drivers of photosynthesis: stomatal conductance (gs), mesophyll conductance (gm) and carbon fixation, mostly driven by RuBisCO carboxylation. Extreme environments shape adaptations in structures, such as cell wall and membrane composition, the concentration and activation state of Calvin–Benson cycle enzymes, and RuBisCO evolution, optimizing kinetic traits to ensure functionality. Altogether, these species display a combination of rearrangements, from the whole‐plant level to the molecular scale, to sustain a positive carbon balance in some of the most hostile environments on Earth. Significance Statement: The molecular and physiological mechanisms that drive photosynthesis in vascular species from extreme environments still remain largely unknown. Here we review the different adaptations (from the whole plant to the molecular level) that enable plants to succeed and sustain an annual positive carbon balance under the typical short and harsh growing seasons in these environments. [ABSTRACT FROM AUTHOR]

The ecological and physiological features of some rare psammophilous plant species of Armenia, included in the Red Book of the RA, Calligonum polygonoides, Astragalus paradoxus and Scorzonera gorovanica have been investigated. As a result of the studies, it was found that the above-mentioned species in the conditions of the Yerevan Botanical Garden showed higher indexes of the water regime and the intensity of photosynthesis and transpiration in comparison with samples from “Gorovan Sands” sanctuary. Each of the studied species has adapted to the current conditions of existence and has occupied a certain ecological niche, using its mechanisms for regulating the water regime, the intensity of transpiration and photosynthesis for this purpose. However, all these species have a certain ecological plasticity, which allowed them to adapt to new, different conditions in the Yerevan Botanical Garden. [ABSTRACT FROM AUTHOR]

The whitefly, Aleurodicus coccolobae (Quaintance and Baker), was recorded for the first time at Nayarit, Mexico, attacking leaves of the bird of paradise plant. This species damages the plant by sucking leaf sap and producing honeydew, thus promoting sooty mold. The sticky substance gives dark coloration to the foliage, which reduces the photosynthesis process. The presence of whiteflies and fungi depreciates the commercial value of flower arrangements and ornamental plants. [ABSTRACT FROM AUTHOR]

Leaf respiration and photosynthesis will respond differently to an increase in temperature during night, which can be more relevant in sensitive ecosystems such as Antarctica. We postulate that the plant species able to colonize the Antarctic Peninsula – Colobanthus quitensis (Kunth) Bartl. and Deschampsia antarctica Desv. – are able to acclimate their foliar respiration and to maintain photosynthesis under nocturnal warming to sustain a positive foliar carbon balance. We conducted a laboratory experiment to evaluate the effect of time of day (day and night) and nocturnal warming on dark respiration. Short (E0 and Q10) and long‐term acclimation of respiration, leaf carbohydrates, photosynthesis (Asat) and foliar carbon balance (R/A) were evaluated. The results suggest that the two species have differential thermal acclimation respiration, where D. antarctica showed more thermosensitivity to short‐term changes in temperature than C. quitensis. Experimental nocturnal warming affected respiration at daytime differentially between the two species, with a significant increase of R10 and Asat in D. antarctica, while no changes on respiration were observed in C. quitensis. Long thermal treatments of the plants indicated that nocturnal but not diurnal respiration could acclimate in both species, and to a greater extent in C. quitensis. Non‐structural carbohydrates were related with respiration in C. quitensis but not in D. antarctica, suggesting that respiration in the former species is likely controlled by total soluble sugars and starch during day and night, respectively. Finally, foliar carbon balance was differentially improved under warming conditions in Antarctic plants by different mechanisms, with C. quitensis deploying respiratory acclimation, while D. antarctica increased its Asat. [ABSTRACT FROM AUTHOR]

Tradescantia fluminensis is an invasive plant species in New Zealand, Australia and parts of the USA. It reproduces vegetatively and can grow to form dense mats up to 60 cm deep. Growth is limited by available light, and shading is one of the few effective methods of control. In this paper, we develop a dynamic model of a vertical cross section of a T. fluminensis mat, capturing vertical variation in its biomass and internal light intensity. We measure both variables at different heights in experimental mats of the species and use these data to parameterize the model. The model produces realistic vertical biomass and light intensity profiles. We show that the mat grows to a steady-state biomass that depends only on: (i) the light absorption coefficient, which we estimate from experimental data and (ii) the ratio of photosynthesis to respiration rate. This steady state undergoes a transcritical bifurcation; when the ambient light intensity falls below a critical level, the biomass shrinks to zero and the mat cannot survive. [ABSTRACT FROM AUTHOR]

Summary: Fossil plant gas‐exchange‐based CO2 reconstructions use carbon (C) assimilation rates of extant plant species as substitutes for assimilation rates of fossil plants. However, assumptions in model species adoption can lead to systematic error propagation.We used a dataset of c. 2500 extant species to investigate the role of phylogenetic relatedness and ecology in determining C assimilation, an essential variable in gas‐exchange‐based CO2 models. We evaluated the effect on random and systematic error propagation in atmospheric CO2 caused by adopting different model species.Phylogenetic relatedness, growth form, and solar exposure are important predictors of C assimilation rate. CO2 reconstructions that apply C assimilation rates from modern species based solely on phylogenetic relatedness to fossil species can result in CO2 estimates that are systematically biased by a factor of > 2.C assimilation rates used in CO2 reconstructions should be determined by averaging assimilation rates of modern plant species that are (1) in the same family and (2) have a similar habit and habitat as the fossil plant. In addition, systematic bias potential and random error propagation are greatly reduced when CO2 is reconstructed from multiple fossil plant species with different modern relatives at the same site. [ABSTRACT FROM AUTHOR]

Summary: Nocturnal stomatal conductance contributes to water loss at night without carbon gain in C3 or C4 plants because photosynthesis does not occur in the dark. The functional relevance of nocturnal conductance thus remains an unresolved conundrum. Here, we review and re‐analyse previously published datasets on nocturnal conductance (gn) globally (176 species) to synthesize our current understanding on its potential biological function and to identify remaining research gaps. We found that gn was positively correlated with relative growth rate, which is compatible with the postulate that circadian‐driven nocturnal conductance enhances predawn stomatal conductance, thereby priming stomata for photosynthesis in early daylight. The variation in gn across plant species and functional types was not consistent with the hypotheses that the main function of gn is to: remove excess CO2, which might limit growth; enhance oxygen delivery to the functional sapwood; enhance nutrient supply; or that gn is due to stomatal leakiness. We suggest further study regarding the potential of gn to be an important functional and ecological trait influencing competitive outcomes and we outline a research programme to achieve that objective. [ABSTRACT FROM AUTHOR]

Copyright of Revista Chapingo Serie Ciencias Forestales is the property of Universidad Autonoma Chapingo and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Highlights from the article: Enhancing soil N availability, plant N uptake and leaf N con- Than soil N availability, determines leaf N concentrations of S B N S × B S × N B × N S × B × N B N B × N B N B × N B N B × N.

Here, we summarize diverse evidence from species that belong to the genus Tradescantia, which we propose as handy and versatile models for studies of the ecology of photosynthesis and the mechanisms of photoacclimation in higher plants. A valuable feature of this genus is the amazingly broad range of ecological niches occupied by its species: from shady understory of tropical rainforest to deserts and semideserts. The former habitats demand shade tolerance (e.g. that featured by Tradescantia fluminensis), whereas the latter requires succulence and/or high light stress tolerance (evident in e.g. Tradescantia navicularis). At the same time, the acclimative traits of Tradescantia species seem quite moderate at first glance. Certainly, their basic principles of acclimation seem to differ in some aspects from the ones typical for most of other higher plants. This review presents a systematic analysis of irradiance responses of Tradescantia species studied on different timescales. The specifics of Tradescantia responses to irradiance make the plants of this genus a 'multitool' for studies in this field. Similarity of irradiance acclimation patterns is a characteristic feature in the ecologically contrasting Tradescantia species, which may inspire further insights into physiology and evolution of plants. [ABSTRACT FROM AUTHOR]

Highlights • Study of photosynthesis characteristics by growth form and domestication, both under well-watered and water-stressed conditions. • Tendency in crop species within each growth form to increase assimilation and reduce mesophyll diffusion resistance. • Herbaceous and crop species present lower mesophyll limitations: different response to drought according to growth form. • Limited photosynthesis improvement so far; importance of considering photosynthesis characteristics for crop improvement. Abstract Photosynthesis is a complex process that is intrinsically determined by two main components: the CO 2 diffusion from the atmosphere to the chloroplast and the biochemistry. Among CO 2 diffusion, mesophyll conductance within the leaf (g m) has been receiving attention in the recent years as a key player determining photosynthesis both across species and in response to the environment; furthermore, g m estimation allows for disentangling the complete set of photosynthesis underlying mechanisms. In a water-limited scenario where crop productivity and efficiency need to be increased, the analysis of available data from photosynthesis among vascular plants and its response to water stress results helpful for a better understanding of crop management and improvement. Here, photosynthesis data are compiled to elucidate if crop and wild species from different growth forms present different photosynthesis limitations under optimum and water stress conditions. From the available data, a double process of apparent photosynthesis selection is revealed: higher values from ferns to woody and herbaceous species and, among angiosperms, a tendency towards greater photosynthesis in crop species (although constrained by growth form). The causes of such photosynthesis variation are discussed. Moreover, crop and herbaceous species present a shift in photosynthesis limitations towards lower mesophyll diffusion constraints, under both well-watered and water-stress conditions. These particular photosynthesis characteristics in crops present several implications for the possible improvement of CO 2 assimilation and water use efficiency, providing new guidelines for future engineering and management in agriculture. [ABSTRACT FROM AUTHOR]