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Straw returning to the field is a technical measure of crop production widely adopted in arid areas. It is unknown whether crop yield can be further increased by improving the eco-physiological characteristics when straw returning is applied in the crop production system. So, a three-year field experiment was conducted with various straw returning treatments for wheat production: (i) no-tillage with straw mulching (NTSM), (ii) no-tillage with straw standing (NTSS), (iii) conventional tillage with straw incorporation (CTS), and (iv) conventional tillage with no straw returning (CT, control). The eco-physiological and yield formation indicators were investigated to provide the basis for selecting the appropriate straw returning method to increase wheat yield and clarifying its regulation mechanism on eco-physiology. The results showed that NTSM and NTSS treatments had better regulation of eco-physiological characteristics and had a higher yield increase than CTS and CT. Meanwhile, NTSM had a relatively higher yield than NTSS through better regulation of eco-physiological characteristics. Compared to CT, the leaf area index of NTSM was decreased by 6.1–7.6% before the Feekes 10.0 stage of wheat, but that of NTSM was increased by 38.9–45.1% after the Feekes 10.0 stage. NTSM effectively regulated the dynamics of the photosynthetic source of green leaves during the wheat growth period. NTSM improved net photosynthetic rate by 10.2–21.4% and 11.0–21.6%, raised transpiration rate by 4.4–10.0% and 5.3–6.1%, increased leaf water use efficiency by 5.6–10.4% and 5.4–14.6%, at Feekes 11.0 and 11.2 stages of wheat, compared to CT, respectively. NTSM had higher leaf water potential (LWP) by 7.5–12.0% and soil water potential (SWP) by 8.9–24.0% from Feekes 10.3 to 11.2 stages of wheat than CT. Meanwhile, the absolute value of difference on LWP and SWP with NTSM was less than that with CT, indicating that NTSM was conducive to holding the stability of water demand for wheat plants and water supply of soil at arid conditions. Thus, NTSM had a greater grain yield of wheat by 18.6–27.3% than CT, and the high yield was attributed to the synchronous increase and cooperative development of ear number, grain number per ear, and 1 000-grain weight. NTSM had a positive effect on regulating the eco-physiological characteristics and can be recommended to enhance wheat grain yield in arid conditions.

Species distributed across a wide elevation range have broad environmental tolerance and adopt specific adaptation strategies to cope with varying climatic conditions. The aim of this study is to understand the patterns of variation in leaf eco-physiological traits that are related to the adaptation of species with a wide distribution in different climatic conditions. We studied the variability in eco-physiological traits of two co-occurring species of Western Himalaya (Rumex nepalensis and Taraxacum officinale), along elevational gradients. We conducted our study in elevations ranging from 1000 to 4000 m a.s.l. in three transects separated in an eco-region spanning 2.5° latitudes and 2.3° longitudes in the Western Himalaya. We hypothesized substantial variation in eco-physiological traits, especially increased net rate of photosynthesis (PN), Rubisco specific activity (RSA), and biochemicals at higher elevations, enabling species to adapt to varying environmental conditions. Therefore, the photosynthetic measurements along with leaf sampling were carried out during the months of June–August and the variations in photosynthetic performance and other leaf traits were assessed. Data was analyzed using a linear mixed effect model with 'species,' 'elevation' as fixed and 'transect' as random factor. Elevation had a significant effect on majority of traits. It was found that PN and maximum carboxylation rate of Rubisco (Vcmax) have unimodal or declining trend along increasing elevations. High RSA was observed at higher elevations in all the three transects. Trends for biochemical traits such as total soluble sugars, total soluble proteins, proline, and total phenolics content suggested an increase in these traits for the survival of plants in harsh environments of higher elevations. Our study reveals that although there is considerable variation in the eco-physiological traits of the two species across elevational gradients of different transects, there are certain similarities in the patterns that depict their high adaptive potential in varying climatic conditions. [ABSTRACT FROM AUTHOR]

Mediterranean almond growing is increasing, as confirmed in Italy where new almond orchards in areas not previously interested in this nut crop have been recently established. In these new areas, as in the coastal of Latium region, the knowledge of eco-physiological behavior as a complex interaction among cultivars, pedoclimate conditions and orchard management is still poor. Optimizing fertilization strategies according to cultivar needs is one of the main key factors to guarantee high yields and nut quality, as well as to reduce environmental pollution. With this aim, an almond field collection has been established planting medium- and late-bloom cultivars. During the growing seasons 2019–2020, leaf samples were collected at 90 and 120 days after full bloom (DAFB) analyzed for biometrical and eco-physiological traits and leaf nutrients content through foliar diagnostics. Differences in foliar nutrient content depend on both cultivar and phenological stage. According to Pearson correlation heatmap, leaf nitrogen content showed a medium–high positive correlation with Nitrogen Balance Index (NBI) either at 90 or 120 DAFB, highlighting reciprocal influences among leaf nutrient contents and some eco-physiological traits. The findings of this study will help to develop novel environmentally friendly nutrition and fertigation strategies supported by foliar diagnostics which also consider accurate cultivar requirements. [ABSTRACT FROM AUTHOR]

Increased anthropogenic nutrient loading has led to eutrophication of aquatic ecosystems, which is the major cause of harmful cyanobacteria blooms. Element stoichiometry of cyanobacteria bloom is subject to nutrient availabilities and may significantly contribute to primary production and biogeochemical cycling. Phycobilisome is the antenna of the photosynthetic pigment apparatus in cyanobacteria, which contains phycobilin pigments (PBPs) and linker proteins. This nitrogen (N)-rich protein complex has the potential to support growth as a N-storage site and may play a major role in the variability of cyanobacteria N stoichiometry. However, the regulation of PBPs during bloom formation remains unclear. We investigated the temporal variation of N allocation into PBPs and element stoichiometry for two ubiquitous cyanobacteria species, Microcystis aeruginosa and Dolichospermum flos-aquae , in a batch culture experiment with different initial N availabilities. Our results indicated that the N allocation into PBPs is species-dependent and tightly regulated by the availability of nutrients fueling population expansion. During the batch culture experiment, different nutrient uptake rates led to distinct stoichiometric imbalances of N and phosphorus (P), which substantially altered cyanobacteria C: N and C: P stoichiometry. Microcystis invested cellular N into PBPs and exhibited greater flexibility in C: N and C: P stoichiometry than D. flos-aquae. The dynamics of such N-rich macromolecules may help explain the N stoichiometry variation during a bloom and the interspecific difference between M. aeruginosa and D. flos-aquae. Our study provides a quantitative understanding of the elemental stoichiometry and the regulation of PBPs for non-diazotrophic and diazotrophic cyanobacteria blooms. [ABSTRACT FROM AUTHOR]

Introduction Bean (Phaseolus vulgaris L.) is one of the most important food sources of human. It has a high nutritional value due to its protein, vitamins and fiber supply. Abiotic stresses are most important limiting factors to crop productivity that among these, drought stress is known to be the main limiting factor of bean production in worldwide. The bean has a low tolerance to water stress, while about 60% of the bean crop is obtained in areas under low water stress. It has been reported that about 25% reduction of yield bean is due to drought stress conditions. The use of modern irrigation methods in addition raise grain yield, because saves of water consumption. Materials and methods In order to investigate the effect of different irrigation regimes on gas exchanges and agronomy traits related to yield in bean, a field experiment was carried out at the Research Farm of the Faculty of Agriculture, Zanjan University, Zanjan, Iran (36410N, 48290E) in spring 2012 years. The experiment was conducted at complete randomized block design with four replications. Experimental treatments included five level of irrigation (Traditional Irrigation with 100 % supply water requirement (I1), drip tape irrigation with 100 (I2), 80 (I3), 60 (I4) and 40 % (I5) supply water requirement. Each plot consisted of four rows, each measuring six meter long, distance of each rows and plants was 50 and 10 cm, respectively. Crop Evapotranspiration (ETc) of bean determined through calculation the evapotranspiration of the refrence crop (ETo) evaluated by FAO-Penman-Montith method and Crop Evapotranspiration (ETc) of plant. For of photosynthesis and other gas exchange parameters use IRGA Lci meter. At the physiological maturity stage, plants in an area of 1 m2 to measuring of length of plant, number pod in plan, number seed in pod, weight of thousand seeds, grain yield, biological yield and harvest index (HI) were harvested, then all aboveground dry matter were determined. Results and discussion The irrigation regimes have significant effect all traits investigate except plant length and intercellular CO2 concentration (Ci). Reducing the amount of available water had adverse effects on the yield and yield components. The maximum of Stomatal conductance to water vapour (gs) observed in I1 and net CO2 assimilation rate (ACO2), mesophyll conductance (gm) in I1 and I2 treatment. The intercellular CO2 concentration (Ci) was not affected by the irrigation regimes. The maximum of grain yield (945.6 kg/h), number of pod in plant (10.95) and harvest index (23.87 %) observed in I2 treatment and the highest of stomatal conductance to water vapour (gs) with 0.43 mmol.m-2s-1 was in I1 treatment. There was no difference in other traits investigate between I1 and I2 treatments. The intercellular CO2 concentration (Ci) not significant in different irrigation regimes. The grain yield, number of pod in plant and harvest index in I2 treatment was more than I1 treatment to the amount 31.29, 59 and 18.93 percent, respectively. Conclusions According to this study, results showed that the physiological and agronomical traits that affected the growth and development of common bean disturbed whit reducing the available water content and ultimately the yield reduced. Since the no significant difference between more eco-physiological traits, in order to reducing of water consumption, suggested that in the field of bean culture, instead of traditional (leakage) irrigation, to use from of drip irrigation method with 100 percent supply water requirement. Result showed that the use of drip tape irrigation with 100 % water requirement was better than traditional irrigation with 100 percent supply water requirement, because in addition raise grain yield, cause saves of water consumption and reduces of hardness of work in farm conditions.

Increased anthropogenic nutrient loading has led to eutrophication of aquatic ecosystems, which is the major cause of harmful cyanobacteria blooms. Element stoichiometry of cyanobacteria bloom is subject to nutrient availabilities and may significantly contribute to primary production and biogeochemical cycling. Phycobilisome is the antenna of the photosynthetic pigment apparatus in cyanobacteria, which contains phycobilin pigments (PBPs) and linker proteins. This nitrogen (N)-rich protein complex has the potential to support growth as a N-storage site and may play a major role in the variability of cyanobacteria N stoichiometry. However, the regulation of PBPs during bloom formation remains unclear. We investigated the temporal variation of N allocation into PBPs and element stoichiometry for two ubiquitous cyanobacteria species, Microcystis aeruginosa and Dolichospermum flos-aquae, in a batch culture experiment with different initial N availabilities. Our results indicated that the N allocation into PBPs is species-dependent and tightly regulated by the availability of nutrients fueling population expansion. During the batch culture experiment, different nutrient uptake rates led to distinct stoichiometric imbalances of N and phosphorus (P), which substantially altered cyanobacteria C: N and C: P stoichiometry. Microcystis invested cellular N into PBPs and exhibited greater flexibility in C: N and C: P stoichiometry than D. flos-aquae. The dynamics of such N-rich macromolecules may help explain the N stoichiometry variation during a bloom and the interspecific difference between M. aeruginosa and D. flos-aquae. Our study provides a quantitative understanding of the elemental stoichiometry and the regulation of PBPs for non-diazotrophic and diazotrophic cyanobacteria blooms.

Mediterranean almond growing is increasing, as confirmed in Italy where new almond orchards in areas not previously interested in this nut crop have been recently established. In these new areas, as in the coastal of Latium region, the knowledge of eco-physiological behavior as a complex interaction among cultivars, pedoclimate conditions and orchard management is still poor. Optimizing fertilization strategies according to cultivar needs is one of the main key factors to guarantee high yields and nut quality, as well as to reduce environmental pollution. With this aim, an almond field collection has been established planting medium- and late-bloom cultivars. During the growing seasons 2019–2020, leaf samples were collected at 90 and 120 days after full bloom (DAFB) analyzed for biometrical and eco-physiological traits and leaf nutrients content through foliar diagnostics. Differences in foliar nutrient content depend on both cultivar and phenological stage. According to Pearson correlation heatmap, leaf nitrogen content showed a medium–high positive correlation with Nitrogen Balance Index (NBI) either at 90 or 120 DAFB, highlighting reciprocal influences among leaf nutrient contents and some eco-physiological traits. The findings of this study will help to develop novel environmentally friendly nutrition and fertigation strategies supported by foliar diagnostics which also consider accurate cultivar requirements.

Understanding how plants superpass high altitude and survive successfully in life-threatning abiotic condition is crucial for predicting their response to climate change. Plant strategies to beat cold are characterized by morphological and physiological adjustments. Here we studied the variations in leaf anatomy and physiology of two grasses Cenchrus ciliaris (Cc) and Imperata cylindrica (Ic) dominating in western Himalayan grasslands which are driven by elevation. We collected leaves of each grass from upper most canopy from three different elevations of district Poonch viz., lower site Paniola (1310 m a.s.l.), middle site Banjosa (1780 m a.s.l.) and higher site Tarkhul (2100 m a.s.l). Results showed that both grasses dodge the aggressive climatic forces by modifying anatomical setting and changing physiological adjustments. Elevation controls the conductive tissues by reducing vessel size and extensive sclerified tissues around the vascular bundles help the plant to avoid cavitation induced in cold conditions. The better physiological adjustment of these grasses at high elevation is ascribed to high proline and sugar present in leaves and accelerated activities of catalase (CAT) and peroxidase (POD) show scavenging ability of these grasses at high altitude. The low activity of malondialdehyde (MDA) is related with lower lipid peroxidation. These results bring novel information on how ecological factors influence the evolution of anatomical and physiological adaptations in high altitude plants. [ABSTRACT FROM AUTHOR]

Functional traits capture characteristics of organisms that determine their individual response to environmental pressures, providing a mechanistic understanding of habitat responses and the effects on ecological processes. Trait-based approaches have already been reported for separate soil groups like bacteria, nematodes and collembolans but investigating these groups together could bring better insights in assessing both environmental pressures and state of the systems. Still, selecting a suite of single traits that might encompass the large heterogeneity in soil biota remains a challenge for community trait-based analyses. We sampled arable fields and their adjacent (buffer zone) margins to investigate overall trait-based responses of the soil community to agricultural management. We explored the suitability of three groups of functional traits (i.e. eco-physiological traits, behavioural traits and faunal morphological traits) to analyse how different components of the soil biota (fungi, bacteria, micro- and mesofauna) respond to agricultural management and to what extent the selected traits detect effects on soil functioning. For microbes, we opted for eco-physiological trait proxies due to the difficulties to study these organisms at individual level. Our results showed that eco-physiological traits reflected differences in nutrient cycling dynamics and carbon storage driven by the soil microbial community. The structural organization of micro- and the mesofauna trophic grouping and body mass distribution reflected effects of agricultural management on soil assemblages and revealed differences in the responses of these groups to the environment. We recognize some methodological limitations of our comprehensive community trait-based approach. Yet our analysis reveals characteristics of the soil community structure and belowground ecological processes, as i.e. the partial shift from the bacterial- to the fungal-driven energy channels, that could not be detected by traditional methods, showing the potential of this approach in determining environmental pressures and in evaluating ecosystem services. [ABSTRACT FROM AUTHOR]

The eco-physiological responses of three nitrogen-fixing cyanobacteria (N-fixing cyanobacteria), Aphanizomenon gracile, Anabaena minderi, and Ana. torques-reginae, to light were assessed under nutrient saturation. The N-fixing cyanobacteria were isolated into monocultures from a natural bloom in a shallow colored lake and their growth irradiance parameters and pigment composition were assessed. The different ecological traits related to light use (μmax, α, Ik) suggest that these N-fixing cyanobacteria are well adapted to low light conditions at sufficient nutrients, yet interspecific differences were observed. Aphanizomenon gracile and Anabaena minderi had high relative growth rates at low irradiances (ca. 70% of those in high light), low half saturation constant for light-limited growth ( Ik < 9.09 μmol photon m−2 s−1) and high efficiency ( α < 0.11 day−1 μmol photon−1 m2 s). Conversely, Ana. torques-reginae showed poorer light competitiveness: low relative growth rates at low irradiances (ca. 40% of those in high light), low α (0.009 day−1 μmol photon−1 m2 s) and higher Ik (35.5 μmol photon m−2 s−1). Final densities in Aphanizomenon gracile and Anabaena minderi reached bloom densities at irradiances above 30 μmol photon m−2 s−1 with different hierarchy depending on irradiance, whereas Ana. torques-reginae never achieved bloom densities. All species had very low densities at irradiances ≤17 μmol photon m−2 s−1, thus no N-fixing blooms would be expected at these irradiances. Also, under prolonged darkness and at lowest irradiance (0 and 3 μmol photon m−2 s−1) akinetes were degraded, suggesting that in ecosystems with permanently dark sediments, the prevalence of N-fixing cyanobacteria should not be favored. All species displayed peaks of phycocyanin, but no phycoeritrin, probably due to the prevailing red light in the ecosystem from which they were isolated. [ABSTRACT FROM AUTHOR]

Changes in climate and land use are altering fire regimes in many regions across the globe. This work aims to study the influence of wildfire recurrence and burn severity on woody community structure and plant functional traits under different environmental conditions. We selected three study sites along a Mediterranean-Oceanic climatic gradient, where we studied the fire history and burn severity of the last wildfire. Four years after the last wildfire, we established 1776 1-m2 plots where the percentage cover of each woody species was sampled. We calculated (i) structural parameters of the community such as total cover, alpha species richness, evenness and diversity (Shannon diversity index), and (ii) vegetation cover of each functional group (differentiating life forms, eco-physiological traits and regenerative traits). Focusing on community structure, results showed increases in species richness and diversity as wildfire recurrence increased, but this effect was partially counterweighted in the areas affected by high severity. In relation to functional groups, we found that increases in recurrence and severity fostered transition from tree- to shrub-dominated ecosystems. Non-arboreal life form, high specific leaf area, N 2 -fixing capacity, resprouting ability and heat-stimulated germination were advantageous traits under high recurrences and severities, and low seed mass was advantageous under high recurrence situations. We suggest that the strength of the effects of wildfire recurrence and burn severity on vegetation structure and traits might vary with climate, increasing from Oceanic to Mediterranean conditions. In the Mediterranean site, recurrence and severity were strongly related to traits associated with germination (seed mass and heat-stimulated germination), whereas in the Oceanic site the strongest relationships were found with a resprouting-related trait (bud location). This study identifies changes in vegetation structure and composition in scenarios of high recurrence and severity, and provides useful information on plant traits that could be key in enhancing vegetation resilience. Unlabelled Image • Wildfire recurrence and burn severity modify plant species richness and diversity. • High recurrence and severity fosters transition from forests to shrublands. • Several plant traits are advantageous in fire regimes of high recurrence and severity. • Fire recurrence and severity effects on vegetation may vary with climatic conditions. [ABSTRACT FROM AUTHOR]

• Endangered Calycanthus chinensis is not a shade-tolerant species but lives under tree. • C. chinensis has large-thin leaves that are easily damaged by wind in forest edge. • C. chinensis is suitable under sparse forests with canopy density 0.2–0.6. • Block-shaped green spaces in parks have plenty of sparse forests for C. chinensis. • Urban green spaces need to be slightly thinned if used as habitats for C. chinensis. Ex situ conservation in urban areas is an essential complementary approach to in situ conservation in wild areas. In this study, we combined multiple approaches, including vegetation investigations for both natural habitats and urban green spaces, eco-physiological experiments and remote sensing investigations for urban green spaces, to identify potential habitats for introducing the endangered plant species Calycanthus chinensis to urban green spaces. The results showed that (1) C. chinensis prefer living under sparse forests with canopy densities of 20–60%; (2) C. chinensis was not a shade tolerant species due to its chlorophyll a/ b ratio (2.58) being higher than the threshold (2.3) for shade tolerant species; (3) the large and thin leaves of C. chinensis are easily damaged by strong wind, so this species can only live under moderate canopy cover; (4) to maintain a sparse crown for the well-being of C. chinensis , the upper layer trees in urban green spaces need to be thinned slightly; and (5) introducing this endangered species increases biodiversity and ecosystem services of urban green spaces. Finally, this study provides a framework and a case study for using urban green spaces as micro-refuges for endangered species. [ABSTRACT FROM AUTHOR]