Short rotation plantation forestry(SRF)is being widely adopted to increase wood production,in order to meet global demand for wood products.However,to ensure maximum gains from SRF,optimised management regimes need to...Short rotation plantation forestry(SRF)is being widely adopted to increase wood production,in order to meet global demand for wood products.However,to ensure maximum gains from SRF,optimised management regimes need to be established by integrating robust predictions and an understanding of mechanisms underlying tree growth.Hybrid ecophysiological models,such as potentially useable light sum equation(PULSE)models,are useful tools requiring minimal input data that meet the requirements of SRF.PULSE models have been tested and calibrated for different evergreen conifers and broadleaves at both juvenile and mature stages of tree growth with coarse soil and climate data.Therefore,it is prudent to question:can adding detailed soil and climatic data reduce errors in this type of model?In addition,PULSE techniques have not been used to model deciduous species,which are a challenge for ecophysiological models due to their phenology.This study developed a PULSE model for a clonal Populus tomentosa plantation in northern China using detailed edaphic and climatic data.The results showed high precision and low bias in height(m)and basal area(m^(2)·ha^(-1))predictions.While detailed edaphoclimatic data produce highly precise predictions and a good mechanistic understanding,the study suggested that local climatic data could also be employed.The study showed that PULSE modelling in combination with coarse level of edaphic and local climate data resulted in reasonably precise tree growth prediction and minimal bias.展开更多
Photosynthetic rate ( P n ), transpiration rate ( E ), stomatal conductance ( g s ), water use efficiency ( WUE ), intercellular CO 2( C i ) and leaf water potential ( Ψ ) in varieties of soybean ( G...Photosynthetic rate ( P n ), transpiration rate ( E ), stomatal conductance ( g s ), water use efficiency ( WUE ), intercellular CO 2( C i ) and leaf water potential ( Ψ ) in varieties of soybean ( Glycine max (L.) Merr.) measured in the past three decades (1970s, 1980s and 1990s) and their inter_relationships were analyzed. These parameters of soybean changed with development stages. It is shown that there was a strongly positive relationship between the yield of soybean and its net photosynthetic rate. Soybean varieties with high yield potential had higher P n , g s and Ψ than those with low yield potential. Their values of C i were remarkably lower. Such relationship was especially remarkable at the critical stage of pod_bearing. P n of soybean of high yield was obviously higher than that of low yield. Of the different stages, the highest P n was found in the pod_bearing stage and other values were higher, too. P n and Ψ of modern soybean varieties were higher and such was continuing. Increased partitioning of carbon to seed and the size of sink may also be important for yield formation when P n values were remarkably higher in the pod_bearing stage.展开更多
We investigated the combined effects of soil moisture and light intensity on the growth, development and ecophysiological characteristics of one-year old Amorpha fruticosa seedlings. Soil moisture and light intensity ...We investigated the combined effects of soil moisture and light intensity on the growth, development and ecophysiological characteristics of one-year old Amorpha fruticosa seedlings. Soil moisture and light intensity influenced the ecophysiological characteristics of Amorpha fruticosa seedlings. Soil moisture resulted in the decreases of growth rate, individual size, net photosynthetic rate, transpiration rate, leaf water loss rate （WLR）, and biomass accumulation of plant parts, and led to increased leaf water saturation deficit （WSD）. Under water stress, more photosynthetic products were allocated to root growth. With decreasing light intensity, net photosynthetic rate, transpiration rate, chla/b, water saturation deficit, water use efficiency, water loss rate and biomass accumulation declined, while Chla, Chlb, Chla＋b and carotenoids （Car） increased and more photosynthetic products were allocated to stem and leaf growth. Maximum growth vigor, net photosynthetic rate and total biomass accumulation in Amorpha fruticosa seedlings was recorded at 75 80% soil water-holding capacity and 100% light density in greenhouse environments.展开更多
The anatomical and chemical characteristics of a rolling leaf mutant （rlm） of rice （Oryza sativa L.） and its ecophysiological properties in photosynthesis and apoplastic transport were investigated. Compared with ...The anatomical and chemical characteristics of a rolling leaf mutant （rlm） of rice （Oryza sativa L.） and its ecophysiological properties in photosynthesis and apoplastic transport were investigated. Compared with the wild type （WT）, the areas of whole vascular bundles and xylem as well as the ratios of xylem area/whole vascular bundles area and xylem area/phloem area were higher in rim, whereas the area and the width of foliar bulliform cell were lower. The Fourier transform infrared （FTIR） microspectroscopy spectra of foliar cell walls differed greatly between rim and WT. The rim exhibited lower protein and polysaccharide contents of foliar cell walls. An obvious reduction of pectin content was also found in rim by biochemical measurements. Moreover, the rate of photosynthesis was depressed while the conductance of stoma and the intercellular CO2 concentration were enhanced in rim. The PTS fluorescence, which represents the ability of apoplastic transport, was 11% higher in rim than in WT. These results suggest that the changes in anatomical and chemical characteristics of foliar vascular bundles, such as the reduction of proteins, pectins, and other polysaccharides of foliar cell walls, participate in the leaf rolling mutation, and consequently lead to the reduced photosynthetic dynamics and apoplastic transport ability in the mutant.展开更多
Many studies have estimated approximately ranges of thresholds of low soil temperature in the growth and ecophysi-ological traits of trees, but difficultly determined the exact values. To resolve the problem, black sp...Many studies have estimated approximately ranges of thresholds of low soil temperature in the growth and ecophysi-ological traits of trees, but difficultly determined the exact values. To resolve the problem, black spruce （Picea mariana） and jack pine （Pinus banksiana） seedlings were exposed to 5, 10, 15, 20, 25, 30 and 35℃ soil temperature in greenhouses. After 90 days of the treatment, net photosynthetic rate （A）, stomatal conductance （gs）, transpiration rate （E）, water use efficiency （WUE） and specific leaf area （SLA） were measured. This study showed that all the traits had an asymmetrical peak relationship with changing soil temperature, the relationship was well simulated using a cubic curvilinear model, and the exact thresholds could be derived from the second derivative of the model. The results revealed that the thresholds varied among ecophysiological traits and between tree species. In black spruce, the thresholds were 14.1, 14.7, 10.7, 14.4 and 16.2℃ forA, gs, E, WUE and SLA; 15.4, 10.4, 14.7, 16.9 and 10.5℃ for the corresponding traits in jack pine. The lowest thresholds of E in black spruce and gs in jack pine were an indicator representing the minimum requirement of soil temperature for the regular processes of ecophysiology. The highest thresholds of SLA in black spruce and WUE in jack pine suggest they are the most sensitive to decreasing soil temperature and may play an important role in the acclimation. The averaged thresholds were at 14.0 and 13.6℃ for black spruce and jack pine, suggesting that the sensitivity of both species to low soil temperature was quite close.展开更多
Based on the data from experiment, several mathematical models for describing the ecophysiological characteristics ofPlagiomnium acutum and the relationship between photosynthetic active radiation (R)P, temperature of...Based on the data from experiment, several mathematical models for describing the ecophysiological characteristics ofPlagiomnium acutum and the relationship between photosynthetic active radiation (R)P, temperature of atmospheric (T a), relative humidity (H r), concentration of carbon dioxide were established with the method of regression. The biological meanings of the models were analyzed primarily, which showed significance in both theory and application.展开更多
Intertidal marine macroalgae experience periodical exposures during low tide due to their zonational distribution. The duration of such emersion leads to different exposures of the plants to light and aerial CO2, whic...Intertidal marine macroalgae experience periodical exposures during low tide due to their zonational distribution. The duration of such emersion leads to different exposures of the plants to light and aerial CO2, which then affect the physiology of them to different extents. The ecophysiological responses to light and CO2 were investigated during emersion in two red algae Gloiopeltis furcata and Gigartina intermedia, and two brown algae Petalonia fascia and Sargassum hemiphyllum, growing along the Shantou coast of China. The light-saturated net photosynthesis in G. furcata and P. fascia showed an increase followed by slightly desiccation, whereas that in G. intermedia and S. hemiphyllumexhibited a continuous decrease with water loss. In addition, the upper-zonated G. furcata and P. fascia, exhibited higher photosynthetic tolerance to desiccation and required higher light level to saturate their photosynthesis than the lower-zonated G. intermedia and S. hemiphyllum. Desiccation had less effect on dark respiration in these four algae compared with photosynthesis. The light-saturated net photosynthesis increased with increased CO2 concentrations, being saturated at CO2 concentrations higher than the present atmospheric level in G. furcata, G. intermedia and S. hemiphyllum during emersion. It was evident that the relative enhancement of photosynthesis by elevated CO2 in those three algae increased, though the absolute values of photosynthetic enhancement owing to CO2 increase were reduced when the desiccation statuses became more severe. However, in the case of desiccated P. fascia (water loss being greater than 20 %), light saturated net photosynthesis was saturated with current ambient atmospheric CO2 level. It is proposed that increasing atmospheric CO2 will enhance the daily photosynthetic production in intertidal macroalgae by varied extents that were related to the species and zonation.展开更多
Aims Successful invasive plants are often assumed to display significant levels of phenotypic plasticity.Three possible strategies by which phenotypic plasticity may allow invasive plant species to thrive in changing ...Aims Successful invasive plants are often assumed to display significant levels of phenotypic plasticity.Three possible strategies by which phenotypic plasticity may allow invasive plant species to thrive in changing environments have been suggested:(i)via plasticity in morphological or physiological traits,invasive plants are able to maintain a higher fitness than native plants in a range of environ-ments,including stressful or low-resource habitats:a‘Jack-of-all-trades’strategy;(ii)phenotypic plasticity allows the invader to better exploit resources available in low stress or favorable habitats,show-ing higher fitness than native ones:a‘Master-of-some’strategy and(iii)a combination of these abilities,the‘Jack-and-Master’strategy.Methods We evaluated these strategies in the successful invader Taraxacum officinale in a controlled experiment mimicking natural environmen-tal gradients.We set up three environmental gradients consisting of factorial arrays of two levels of temperature/light,temperature/water and light/water,respectively.We compared several ecophysiologi-cal traits,as well as the reaction norm in fitness-related traits,in both T.officinale and the closely related native Hypochaeris thrin-cioides subjected to these environmental scenarios.Important Findings Overall,T.officinale showed significantly greater accumulation of biomass and higher survival than the native H.thrincioides,with this difference being more pronounced toward both ends of each gradient.T.officinale also showed significantly higher plasticity than its native counterpart in several ecophysiological traits.Therefore,T.officinale exhibits a Jack-and-Master strategy as it is able to main-tain higher biomass and survival in unfavorable conditions,as well as to increase fitness when conditions are favorable.We suggest that this strategy is partly based on ecophysiological responses to the environment,and that it may contribute to explaining the successful invasion of T.officinale across different habitats.展开更多
Marine heatwaves(MHWs)caused by anthropogenic climate change are becoming a key driver of change at the ecosystem level.Thermal conditions experienced by marine organisms across their distribution,particularly towards...Marine heatwaves(MHWs)caused by anthropogenic climate change are becoming a key driver of change at the ecosystem level.Thermal conditions experienced by marine organisms across their distribution,particularly towards the equator,are likely to approach their physiological limits,resulting in extensive mortality and subsequent changes at the population level.Populations at the margins of their species’distribution are thought to be more sensitive to climate-induced environmental pressures than central populations,but our understanding of variability in fitness-related physiological traits in trailing versus leading-edge populations is limited.In a laboratory simulation study,we tested whether two leading(Iceland)and two trailing(Spain)peripheral populations of the intertidal macroalga Corallina officinalis display different levels of maximum potential quantum efficiency(Fv/Fm)resilience to current and future winter MHWs scenarios.Our study revealed that ongoing and future local winter MHWs will not negatively affect leading-edge populations of C.officinalis,which exhibited stable photosynthetic efficiency throughout the study.Trailing edge populations showed a positive though non-significant trend in photosynthetic efficiency throughout winter MHWs exposure.Poleward and equatorward populations did not produce significantly different results,with winter MHWs having no negative affect on Fv/Fm of either population.Additionally,we found no long-term regional or population-level influence of a winter MHWs on this species’photosynthetic efficiency.Thus,we found no statistically significant difference in thermal stress responses between leading and trailing populations.Nonetheless,C.officinalis showed a trend towards higher stress responses in southern than northern populations.Because responses rest on a variety of local population traits,they are difficult to predict based solely on thermal pressures.展开更多
Microorganisms represent a substantial portion of the earth’s biodiversity and biomass, and the plant rhizosphere is an innate reservoir teeming with heterogeneous microbes predominated by bacterial communities. Rhiz...Microorganisms represent a substantial portion of the earth’s biodiversity and biomass, and the plant rhizosphere is an innate reservoir teeming with heterogeneous microbes predominated by bacterial communities. Rhizospheric microbial diversity (genetic, phenotypic, and metabolic) has been extensively studied to understand the key ecological roles played by the microbial members, including plant growth promotion. The application of 16S rRNA gene sequencing and next-generation sequencing (NGS) technologies has revolutionized the discovery of novel bacterial groups that have remained undetected by traditional cultivation-based approaches. Such technological advancements have opened new vistas in our current understanding of predominant but concealed and missed bacterial diversity referred to as difficult-to-culture bacterial lineages, especially the predominant phyla Acidobacteria, Verrucomicrobia,Planctomycetes, and Gemmatimonadetes. Regardless of their ubiquity and prevalence, little is known about their ecophysiology because of the non-availability of culturable members. More recently, there has been increased interest in understanding the cosmopolitan distribution and diversity of the difficult-to-culture bacteria, focusing on their role in driving complex plant-microbial interactions and mobilizing nutrients in soil and their potential as sources of novel bioactive metabolites. As an initial step, we review the distribution and significance of such bacterial phyla in soil, their ecophysiological roles, and their hidden plant growth promoting potential. The ability to select and deploy plant probiotic bacteria from the difficult-to-culture fraction of the bacterial community might open new avenues for improving crop health.展开更多
Understanding of treeline ecotone ecophysiological adaptation to climate warming is still very limited. Furthermore, it is difficult to predict which plant species could dominate in the future. For this reason, a stud...Understanding of treeline ecotone ecophysiological adaptation to climate warming is still very limited. Furthermore, it is difficult to predict which plant species could dominate in the future. For this reason, a study was conducted in the treeline ecotone, East Tibetan Plateau to detect the adaptation of the dwarf willow(Salix eriostachya) to experimental warming. Compared to ambient conditions, the experimental warming advanced the bud break by 12 days, delayed the leaf abscission by20 days, and prolonged the growing period by 28 days.It also increased photosynthesis(47%), number of leaves(333%), leaf area(310%), and carbon sequestration of the dwarf willow. Experimental warming did not affect carbon use efficiency, but decreased water use efficiency significantly.Experimental warming enhanced the clonal ramets of Salix eriostachya(+ 3.7 shrubs m-2). The frequent air temperature fluctuations had minor effect on Salix eriostachya. Based on these findings, we highlighted that Salix eriostachya could dominate in the community treeline ecotone of east Tibetan Plateau in the future climate warming scenario.展开更多
Ecological restoration is one of the hot technologies for the reconstruction of eutrophic lake ecosystems in which the restoration and propagation of submerged plants is the key and difficult step. In this paper, the ...Ecological restoration is one of the hot technologies for the reconstruction of eutrophic lake ecosystems in which the restoration and propagation of submerged plants is the key and difficult step. In this paper, the effect of vermiculite on the growth process of Vallisneria spiralis and sediment microenvironment were investigated, aiming to provide a theoretical basis for the application of vermiculite in aquatic ecological restoration. Results of growth indexes demonstrated that 5% and 10% vermiculite treatment groups statistically promote the growth of Vallisneria spiralis compared to the control. Meanwhile, the results of ecophysiological indexes showed that photosynthetic pigment, soluble sugar content, superoxide dismutase(SOD), and catalase(CAT) activity of 5% and 10% group were increased compared with the control while the malondialdehyde(MDA) content exhibited the opposite result(p < 0.05), which illustrated that vermiculite can improve the resistance of plants and delay the aging process of Vallisneria spiralis. In addition, result of PCA(Principal Component Analysis) demonstrated 5% and 10% group has improved the sediment physical conditions and create more ecological niche for microorganisms directly, and then promoted the growth of plants. The dissolution results showed that vermiculite can dissolve the constant and trace elements needed for plant growth. Furthermore, the addition of vermiculite increased the diversity of microorganisms in the sediments, and promoted the increase of plant growth-promoting bacteria and phosphorus-degrading bacteria. This study could provide a technique reference for the further application of vermiculite in the field of ecological restoration.展开更多
The increasingly serious problem of acid rain is leading to increased potassium （K） loss from soils, and in our field investigation, we found that even congenerically relative Mosla species show different tolerance ...The increasingly serious problem of acid rain is leading to increased potassium （K） loss from soils, and in our field investigation, we found that even congenerically relative Mosla species show different tolerance to K-deficiency. A hydroponic study was conducted on the growth of two Mosla species and their morphological, physiological and stoichiometric traits in response to limited （0.35 mmol K/L）, normal （3.25 mmol K/L） and excessive （6.50 mmol K/L） K concentrations. Mosla hangchowensis is an endangered plant, whereas Mosla dianthera a widespread weed. In the case of M. hangchowensis, in comparison with normal K concentration, K-limitation induced a significant reduction in net photosynthetic rate （Pn）, soluble protein content, and superoxide dismutase （SOD） actix, ity, but an increase in malondialdehyde （MDA） concentration. However, leaf mass ratio （LMR） and root mass ratio （RMR） were changed little by K-limitation. In contrast, for M. dianthera, K-limitation had little effect on Pn, soluble protein content, SOD activity, and MDA concentration, but increased LMR and RMR. Critical values of N （nitrogen）：K and K：P （phosphorus） ratios in the shoots indicated that limitation in acquiring K occurred under K-limited conditions for M. hangchowensis but not for M. dianthera. We found that low K content in natural habitats was a restrictive factor in the growth and distribution of M.. hangchowensis, and soil K-deficiency caused by acid rain worsened the situation of M. hangchowensis, while M. dianthera could well acclimate to the increasing K-deficiency. We suggest that controlling the acid rain and applying K fertilizers may be an effective way to rescue the endangered M. hangchowensis.展开更多
Background:Black spruce(Picea mariana(Mill.)BSP)-forested peatlands are widespread ecosystems in boreal North America in which peat accumulation,known as the paludification process,has been shown to induce forest grow...Background:Black spruce(Picea mariana(Mill.)BSP)-forested peatlands are widespread ecosystems in boreal North America in which peat accumulation,known as the paludification process,has been shown to induce forest growth decline.The continuously evolving environmental conditions(e.g.,water table rise,increasing peat thickness)in paludified forests may require tree growth mechanism adjustments over time.In this study,we investigate tree ecophysiological mechanisms along a paludification gradient in a boreal forested peatland of eastern Canada by combining peat-based and tree-ring analyses.Carbon and oxygen stable isotopes in tree rings are used to document changes in carbon assimilation rates,stomatal conductance,and water use efficiency.In addition,paleohydrological analyses are performed to evaluate the dynamical ecophysiological adjustments of black spruce trees to site-specific water table variations.Results:Increasing peat accumulation considerably impacts forest growth,but no significant differences in tree water use efficiency(iWUE)are found between the study sites.Tree-ring isotopic analysis indicates no iWUE decrease over the last 100 years,but rather an important increase at each site up to the 1980 s,before iWUE stabilized.Surprisingly,inferred basal area increments do not reflect such trends.Therefore,iWUE variations do not reflect tree ecophysiological adjustments required by changes in growing conditions.Local water table variations induce no changes in ecophysiological mechanisms,but a synchronous shift in iWUE is observed at all sites in the mid-1980 s.Conclusions:Our study shows that paludification induces black spruce growth decline without altering tree water use efficiency in boreal forested peatlands.These findings highlight that failing to account for paludification-related carbon use and allocation could result in the overestimation of aboveground biomass production in paludified sites.Further research on carbon allocation strategies is of utmost importance to understand the carbon sink capacity of these widespread ecosystems in the context of climate change,and to make appropriate forest management decisions in the boreal biome.展开更多
In past 30 years, the wheat yield per unit area of China has increased by 79%. The super-high-yield(SH) cultivation played an important role in improving the wheat photosynthesis and yield. In order to find the ecophy...In past 30 years, the wheat yield per unit area of China has increased by 79%. The super-high-yield(SH) cultivation played an important role in improving the wheat photosynthesis and yield. In order to find the ecophysiological mechanism underneath the high photosynthesis of SH cultivation, in situ diurnal changes in the photosynthetic gas exchange and chlorophyll(Chl) a fluorescence of field-grown wheat plants during the grain-filling stage and environmental factors were investigated. During the late grain-filling stage at 24 days after anthesis(DAA), the diurnal changes in net CO_(2) assimilation rate were higher under SH treatment than under high-yield(H) treatment. From 8 to 24 DAA, the actual quantum yield of photosystem II(PSII) electron transport in the light-adapted state(ΦPSII) in the flag leaves at noon under SH treatment were significantly higher than those under H treatment. The leaf temperature, soil temperature and soil moisture were better suited for higher rates of leaf photosynthesis under SH treatment than those under H treatment at noon. Such diurnal changes in environmental factors in wheat fields could be one of the mechanisms for the higher biomass and yield under SH cultivation than those under H cultivation. ΦPSII and CO_(2) exchange rate in wheat flag leaves under SH and H treatments had a linear correlation which could provide new insight to evaluate the wheat photosynthesis performance under different conditions.展开更多
Deserts have traditionally been considered as a low moisture system where biological activity is triggered by unpredictable rainfall in time and space. Studies on desert ecosystems functions, processes, dynamics and d...Deserts have traditionally been considered as a low moisture system where biological activity is triggered by unpredictable rainfall in time and space. Studies on desert ecosystems functions, processes, dynamics and diversity of soil biota had been found to contribute to understanding of their role in primary production and management of soil ecosystems. As belowground biota is very diverse they are playing an important role in above as well below ground essential ecosystem processes e.g. primary production, decomposition, nutrient mineralization etc. The challenge is to use the emerging knowledge of soil biota diversity in understanding basic ecosystems function.展开更多
Raphidiopsis raciborskii is a notorious bloom-forming and filamentous cyanobacterium that has been extensively investigated into its toxicity,phylogeny,and spreading potential.Studies have demonstrated that this speci...Raphidiopsis raciborskii is a notorious bloom-forming and filamentous cyanobacterium that has been extensively investigated into its toxicity,phylogeny,and spreading potential.Studies have demonstrated that this species has spanned different climates from tropical zones to temperate regions,suggesting that R.raciborskii is becoming a cosmopolitan species in freshwater systems around the world.In fact,it has been proposed that several characteristics of R.raciborskii may explain its spread and dominance.In particular,R.raciborskii is known to display a high extent of physiological plasticity regarding nutrients,light regimes,and te mperature s.Moreover,this species illustrates different ecotype s with distinct environmental requirements.Here,we present an overview of R.raciborskii’s global distribution and adaptation strategy based on the recent findings from genome variance,toxicity,and ecophysiology.The expansion of its geographical distribution can be linked to its genome,toxicity,and ecophysiology.The variable genes are mainly associated with the stress response,phage defense,DNA repair,cell cycle control,and membrane transport,illustrating the species’adaptability in response to changing environments.In fact,the species shows rapid adaptability to low and/or variable nutrient availability,especially changing phosphorus availability.Moreover,the variabilities of strains within the population extend their flexibility to adapt and acclimate to ambient environment.In addition,cylindrospermopsins(CYN)appear to have a potential biological role in facilitating theirs dominance or bloom.These strategies of R.raciborskii make it a challenge to manage in a fre shwater system,reflecting the management of its bloom from further evidence of the complex ecophysiology,toxicity,and genome of this species.展开更多
Considering that diverse fire severities can affect soil properties differently,the aim of this study was to examine to what extent changes in soil properties caused by fire could condition seedling establishment.This...Considering that diverse fire severities can affect soil properties differently,the aim of this study was to examine to what extent changes in soil properties caused by fire could condition seedling establishment.This new approach is for identifying a new fire cause-effect chain to qualify the impacts of fire on soils with the purpose of using fire as a tool in forest management to favour Pinus halepensis Mill.regeneration.The study area was a reforested P.halepensis area which had been crossed by fire for78.8 ha,causing various degrees of damage.The forest was subdivided into three large areas according to the gravity of crown scorch,[low(LS),medium(MS)and high(HS)severity],on the basis of needle yellowing which usually occurs after exposure to direct flames.Results showed significant differences in soil properties with respect to fire severity.In the HS area,total nitrogen and carbon were considerably reduced while ash and phosphorus contents significantly increased.The changes in soil properties,in particular to nutrient levels,affected P.halepensis regeneration,mainly the first year after the fire.Greater regeneration occurred in areas affected by moderate fire severity in which the temperatures reached increased the mineralization of soil organic matter with the consequent release of nutrients available for seedling growth.Additionally,moderate fire severity suppressed the regeneration of grasses,reducing the interspecific competition.Heights of seedlings were inversely proportional to the density of grasses.Where the number was abundant(LS),the height was modest;conversely,where the number was low(HS),the greater hypsometric differentiation of pine seedlings was observed.These results suggest that moderate fire severity represents an environmental stress(hormesis)altering microscale conditions to increase pine germination and establishment.The exposure of P.halpensis to a moderate environmental factor that is damaging at higher intensities,induces an adaptive beneficial effect on seedling regeneration.This data can re-evaluate the assertion that coniferous burned areas,if left unmanaged,would remain unproductive for an indefinite period.展开更多
Independence among leaf economics,leaf hydraulics and leaf size confers plants great capability in adapting to heterogeneous environments.However,it remains unclear whether the independence of the leaf traits revealed...Independence among leaf economics,leaf hydraulics and leaf size confers plants great capability in adapting to heterogeneous environments.However,it remains unclear whether the independence of the leaf traits revealed across species still holds within species,especially under stressed conditions.Here,a suite of traits in these dimensions were measured in leaves and roots of a typical mangrove species,Ceriops tagal,which grows in habitats with a similar sunny and hot environment but different soil salinity in southern China.Compared with C.tagal under low soil salinity,C.tagal under high soil salinity had lower photosynthetic capacity,as indicated directly by a lower leaf nitrogen concentration and higher water use efficiency,and indirectly by a higher investment in defense function and thinner palisade tissue;had lower water transport capacity,as evidenced by thinner leaf minor veins and thinner root vessels;and also had much smaller single leaf area.Leaf economics,hydraulics and leaf size of the mangrove species appear to be coordinated as one trait dimension,which likely stemmed from covariation of soil water and nutrient availability along the salinity gradient.The intraspecific leaf trait relationship under a stressful environment is insightful for our understanding of plant adaption to the multifarious environments.展开更多
Tree competitiveness generally depends on trait plasticity in response to environmental change.The effects of nitrogen(N)and phosphorus(P)on leaf trait variability by species is poorly understood,especially in China’...Tree competitiveness generally depends on trait plasticity in response to environmental change.The effects of nitrogen(N)and phosphorus(P)on leaf trait variability by species is poorly understood,especially in China’s subtropical forests.This study examined the seedling leaf traits and net primary productivity of all trees>5 cm DBH of two dominant species,Schima superba and Castanopsis carlesii,in an evergreen broadleaved forest fertilized with nitrogen(+N),phosphorus(+P),and nitrogen plus phosphorus(N+P).The effect of N on seedling leaf traits was stronger than P,while fertilization in general was species dependent.Leaf mass per unit area decreased with N for S.superba seedlings but not for C.carlesii.Leaf N,P,and N/P ratios changed with N addition for both species.All four N fractions of carboxylation,bioenergetics,cell wall,and other N metabolites in C.carlesii leaves responded significantly to fertilization,while only the cell wall in S.superb a leaves responded.Other leaf functional traits,including light-saturated photosynthetic rates,water,N,and P use efficiencies,chlorophyll and non structural carbohydrate contents increased with N addition in S.superb a and by P addition in C.carlesii.Canopy closure at the stand-level increased due to N.Litter biomass and relative growth rate of S.superb a was not affected by any treatments,while both for C.carlesii significantly decreased with N+P addition.Collectively,nutrient limitation may vary at a small scale among species in a subtropical forest based on their responses of seedling traits and net primary productivity to fertilization.Seedling traits are not correlated with the net primary productivity of larger trees except for N fractions,because low light conditions induced by fertilization reduces the proportion of N allocated to photosynthesis in seedlings.In addition,acclimation differences of tree species may increase the uncertainty of community succession.展开更多
基金The National Key Research and Development Program of China(Grant No.2021YFD2201203)the 5·5 Engineering Research&Innovation Team Project of Beijing Forestry University(No.BLRC2023C05)the Key Research and Development Program of Shandong Province(No.2021SFGC02050102)。
文摘Short rotation plantation forestry(SRF)is being widely adopted to increase wood production,in order to meet global demand for wood products.However,to ensure maximum gains from SRF,optimised management regimes need to be established by integrating robust predictions and an understanding of mechanisms underlying tree growth.Hybrid ecophysiological models,such as potentially useable light sum equation(PULSE)models,are useful tools requiring minimal input data that meet the requirements of SRF.PULSE models have been tested and calibrated for different evergreen conifers and broadleaves at both juvenile and mature stages of tree growth with coarse soil and climate data.Therefore,it is prudent to question:can adding detailed soil and climatic data reduce errors in this type of model?In addition,PULSE techniques have not been used to model deciduous species,which are a challenge for ecophysiological models due to their phenology.This study developed a PULSE model for a clonal Populus tomentosa plantation in northern China using detailed edaphic and climatic data.The results showed high precision and low bias in height(m)and basal area(m^(2)·ha^(-1))predictions.While detailed edaphoclimatic data produce highly precise predictions and a good mechanistic understanding,the study suggested that local climatic data could also be employed.The study showed that PULSE modelling in combination with coarse level of edaphic and local climate data resulted in reasonably precise tree growth prediction and minimal bias.
文摘Photosynthetic rate ( P n ), transpiration rate ( E ), stomatal conductance ( g s ), water use efficiency ( WUE ), intercellular CO 2( C i ) and leaf water potential ( Ψ ) in varieties of soybean ( Glycine max (L.) Merr.) measured in the past three decades (1970s, 1980s and 1990s) and their inter_relationships were analyzed. These parameters of soybean changed with development stages. It is shown that there was a strongly positive relationship between the yield of soybean and its net photosynthetic rate. Soybean varieties with high yield potential had higher P n , g s and Ψ than those with low yield potential. Their values of C i were remarkably lower. Such relationship was especially remarkable at the critical stage of pod_bearing. P n of soybean of high yield was obviously higher than that of low yield. Of the different stages, the highest P n was found in the pod_bearing stage and other values were higher, too. P n and Ψ of modern soybean varieties were higher and such was continuing. Increased partitioning of carbon to seed and the size of sink may also be important for yield formation when P n values were remarkably higher in the pod_bearing stage.
基金supported by National Science Foundation of China (No.31270374)Independent Innovation Foundation of Shandong University (No.2011DX008)+1 种基金Natural Science Foundation of Shandong Province,China (No.2009ZRB01875ZR2010CM062)
文摘We investigated the combined effects of soil moisture and light intensity on the growth, development and ecophysiological characteristics of one-year old Amorpha fruticosa seedlings. Soil moisture and light intensity influenced the ecophysiological characteristics of Amorpha fruticosa seedlings. Soil moisture resulted in the decreases of growth rate, individual size, net photosynthetic rate, transpiration rate, leaf water loss rate （WLR）, and biomass accumulation of plant parts, and led to increased leaf water saturation deficit （WSD）. Under water stress, more photosynthetic products were allocated to root growth. With decreasing light intensity, net photosynthetic rate, transpiration rate, chla/b, water saturation deficit, water use efficiency, water loss rate and biomass accumulation declined, while Chla, Chlb, Chla＋b and carotenoids （Car） increased and more photosynthetic products were allocated to stem and leaf growth. Maximum growth vigor, net photosynthetic rate and total biomass accumulation in Amorpha fruticosa seedlings was recorded at 75 80% soil water-holding capacity and 100% light density in greenhouse environments.
基金supported by the National Natural Science Foundation of China (Grant No. 30470274)the Zhejiang Natural Science Foundation of China (Grant No. Y306087)the Zijin Program of Zhejiang University for Young Teachers, China.
文摘The anatomical and chemical characteristics of a rolling leaf mutant （rlm） of rice （Oryza sativa L.） and its ecophysiological properties in photosynthesis and apoplastic transport were investigated. Compared with the wild type （WT）, the areas of whole vascular bundles and xylem as well as the ratios of xylem area/whole vascular bundles area and xylem area/phloem area were higher in rim, whereas the area and the width of foliar bulliform cell were lower. The Fourier transform infrared （FTIR） microspectroscopy spectra of foliar cell walls differed greatly between rim and WT. The rim exhibited lower protein and polysaccharide contents of foliar cell walls. An obvious reduction of pectin content was also found in rim by biochemical measurements. Moreover, the rate of photosynthesis was depressed while the conductance of stoma and the intercellular CO2 concentration were enhanced in rim. The PTS fluorescence, which represents the ability of apoplastic transport, was 11% higher in rim than in WT. These results suggest that the changes in anatomical and chemical characteristics of foliar vascular bundles, such as the reduction of proteins, pectins, and other polysaccharides of foliar cell walls, participate in the leaf rolling mutation, and consequently lead to the reduced photosynthetic dynamics and apoplastic transport ability in the mutant.
基金supported by the Lakehead University Graduate Fellowship, Nature Science and Engineer Research Council Scholarship of Canada (NSERC) PGS A,the National Natural Science Foundation of China (Grant No. 30872000)K. C. Wong Education Foundation of Hong Kong (2008) and the funding initiative of Institute of Mountain Hazards and Environment, Chinese Academy of Sciences to the author and NSERC research grant to Qing-Lai Dang
文摘Many studies have estimated approximately ranges of thresholds of low soil temperature in the growth and ecophysi-ological traits of trees, but difficultly determined the exact values. To resolve the problem, black spruce （Picea mariana） and jack pine （Pinus banksiana） seedlings were exposed to 5, 10, 15, 20, 25, 30 and 35℃ soil temperature in greenhouses. After 90 days of the treatment, net photosynthetic rate （A）, stomatal conductance （gs）, transpiration rate （E）, water use efficiency （WUE） and specific leaf area （SLA） were measured. This study showed that all the traits had an asymmetrical peak relationship with changing soil temperature, the relationship was well simulated using a cubic curvilinear model, and the exact thresholds could be derived from the second derivative of the model. The results revealed that the thresholds varied among ecophysiological traits and between tree species. In black spruce, the thresholds were 14.1, 14.7, 10.7, 14.4 and 16.2℃ forA, gs, E, WUE and SLA; 15.4, 10.4, 14.7, 16.9 and 10.5℃ for the corresponding traits in jack pine. The lowest thresholds of E in black spruce and gs in jack pine were an indicator representing the minimum requirement of soil temperature for the regular processes of ecophysiology. The highest thresholds of SLA in black spruce and WUE in jack pine suggest they are the most sensitive to decreasing soil temperature and may play an important role in the acclimation. The averaged thresholds were at 14.0 and 13.6℃ for black spruce and jack pine, suggesting that the sensitivity of both species to low soil temperature was quite close.
文摘Based on the data from experiment, several mathematical models for describing the ecophysiological characteristics ofPlagiomnium acutum and the relationship between photosynthetic active radiation (R)P, temperature of atmospheric (T a), relative humidity (H r), concentration of carbon dioxide were established with the method of regression. The biological meanings of the models were analyzed primarily, which showed significance in both theory and application.
基金funded by the National Natural Science Foundation of China under contract Nos 30470343,30300050 and 39830060the Guangdong Natural Science Foundation under contract No.04010990.
文摘Intertidal marine macroalgae experience periodical exposures during low tide due to their zonational distribution. The duration of such emersion leads to different exposures of the plants to light and aerial CO2, which then affect the physiology of them to different extents. The ecophysiological responses to light and CO2 were investigated during emersion in two red algae Gloiopeltis furcata and Gigartina intermedia, and two brown algae Petalonia fascia and Sargassum hemiphyllum, growing along the Shantou coast of China. The light-saturated net photosynthesis in G. furcata and P. fascia showed an increase followed by slightly desiccation, whereas that in G. intermedia and S. hemiphyllumexhibited a continuous decrease with water loss. In addition, the upper-zonated G. furcata and P. fascia, exhibited higher photosynthetic tolerance to desiccation and required higher light level to saturate their photosynthesis than the lower-zonated G. intermedia and S. hemiphyllum. Desiccation had less effect on dark respiration in these four algae compared with photosynthesis. The light-saturated net photosynthesis increased with increased CO2 concentrations, being saturated at CO2 concentrations higher than the present atmospheric level in G. furcata, G. intermedia and S. hemiphyllum during emersion. It was evident that the relative enhancement of photosynthesis by elevated CO2 in those three algae increased, though the absolute values of photosynthetic enhancement owing to CO2 increase were reduced when the desiccation statuses became more severe. However, in the case of desiccated P. fascia (water loss being greater than 20 %), light saturated net photosynthesis was saturated with current ambient atmospheric CO2 level. It is proposed that increasing atmospheric CO2 will enhance the daily photosynthetic production in intertidal macroalgae by varied extents that were related to the species and zonation.
文摘Aims Successful invasive plants are often assumed to display significant levels of phenotypic plasticity.Three possible strategies by which phenotypic plasticity may allow invasive plant species to thrive in changing environments have been suggested:(i)via plasticity in morphological or physiological traits,invasive plants are able to maintain a higher fitness than native plants in a range of environ-ments,including stressful or low-resource habitats:a‘Jack-of-all-trades’strategy;(ii)phenotypic plasticity allows the invader to better exploit resources available in low stress or favorable habitats,show-ing higher fitness than native ones:a‘Master-of-some’strategy and(iii)a combination of these abilities,the‘Jack-and-Master’strategy.Methods We evaluated these strategies in the successful invader Taraxacum officinale in a controlled experiment mimicking natural environmen-tal gradients.We set up three environmental gradients consisting of factorial arrays of two levels of temperature/light,temperature/water and light/water,respectively.We compared several ecophysiologi-cal traits,as well as the reaction norm in fitness-related traits,in both T.officinale and the closely related native Hypochaeris thrin-cioides subjected to these environmental scenarios.Important Findings Overall,T.officinale showed significantly greater accumulation of biomass and higher survival than the native H.thrincioides,with this difference being more pronounced toward both ends of each gradient.T.officinale also showed significantly higher plasticity than its native counterpart in several ecophysiological traits.Therefore,T.officinale exhibits a Jack-and-Master strategy as it is able to main-tain higher biomass and survival in unfavorable conditions,as well as to increase fitness when conditions are favorable.We suggest that this strategy is partly based on ecophysiological responses to the environment,and that it may contribute to explaining the successful invasion of T.officinale across different habitats.
基金The Fundação para a Ciência e Tecnologia(FCT-MEC,Portugal)under contract No.UIDB/04326/2020 awarded to Gerardo Zardithe South African Research Chairs Initiative(SARChI)of the Department of Science and Technology and the National Research Foundation of South Africa under contract No.64801 awarded to Christopher McQuaid+1 种基金the Fund of European Union’s Horizon 2020 Research and Innovation Programme under the Marie Skłodowska-Curie contract No.101034329the WINNINGNormandy Program supported by the Normandy Region for Gerardo Zardi.
文摘Marine heatwaves(MHWs)caused by anthropogenic climate change are becoming a key driver of change at the ecosystem level.Thermal conditions experienced by marine organisms across their distribution,particularly towards the equator,are likely to approach their physiological limits,resulting in extensive mortality and subsequent changes at the population level.Populations at the margins of their species’distribution are thought to be more sensitive to climate-induced environmental pressures than central populations,but our understanding of variability in fitness-related physiological traits in trailing versus leading-edge populations is limited.In a laboratory simulation study,we tested whether two leading(Iceland)and two trailing(Spain)peripheral populations of the intertidal macroalga Corallina officinalis display different levels of maximum potential quantum efficiency(Fv/Fm)resilience to current and future winter MHWs scenarios.Our study revealed that ongoing and future local winter MHWs will not negatively affect leading-edge populations of C.officinalis,which exhibited stable photosynthetic efficiency throughout the study.Trailing edge populations showed a positive though non-significant trend in photosynthetic efficiency throughout winter MHWs exposure.Poleward and equatorward populations did not produce significantly different results,with winter MHWs having no negative affect on Fv/Fm of either population.Additionally,we found no long-term regional or population-level influence of a winter MHWs on this species’photosynthetic efficiency.Thus,we found no statistically significant difference in thermal stress responses between leading and trailing populations.Nonetheless,C.officinalis showed a trend towards higher stress responses in southern than northern populations.Because responses rest on a variety of local population traits,they are difficult to predict based solely on thermal pressures.
文摘Microorganisms represent a substantial portion of the earth’s biodiversity and biomass, and the plant rhizosphere is an innate reservoir teeming with heterogeneous microbes predominated by bacterial communities. Rhizospheric microbial diversity (genetic, phenotypic, and metabolic) has been extensively studied to understand the key ecological roles played by the microbial members, including plant growth promotion. The application of 16S rRNA gene sequencing and next-generation sequencing (NGS) technologies has revolutionized the discovery of novel bacterial groups that have remained undetected by traditional cultivation-based approaches. Such technological advancements have opened new vistas in our current understanding of predominant but concealed and missed bacterial diversity referred to as difficult-to-culture bacterial lineages, especially the predominant phyla Acidobacteria, Verrucomicrobia,Planctomycetes, and Gemmatimonadetes. Regardless of their ubiquity and prevalence, little is known about their ecophysiology because of the non-availability of culturable members. More recently, there has been increased interest in understanding the cosmopolitan distribution and diversity of the difficult-to-culture bacteria, focusing on their role in driving complex plant-microbial interactions and mobilizing nutrients in soil and their potential as sources of novel bioactive metabolites. As an initial step, we review the distribution and significance of such bacterial phyla in soil, their ecophysiological roles, and their hidden plant growth promoting potential. The ability to select and deploy plant probiotic bacteria from the difficult-to-culture fraction of the bacterial community might open new avenues for improving crop health.
基金National Natural Science Foundation of China(NSFC)(Grant Nos.31170423,31200375)
文摘Understanding of treeline ecotone ecophysiological adaptation to climate warming is still very limited. Furthermore, it is difficult to predict which plant species could dominate in the future. For this reason, a study was conducted in the treeline ecotone, East Tibetan Plateau to detect the adaptation of the dwarf willow(Salix eriostachya) to experimental warming. Compared to ambient conditions, the experimental warming advanced the bud break by 12 days, delayed the leaf abscission by20 days, and prolonged the growing period by 28 days.It also increased photosynthesis(47%), number of leaves(333%), leaf area(310%), and carbon sequestration of the dwarf willow. Experimental warming did not affect carbon use efficiency, but decreased water use efficiency significantly.Experimental warming enhanced the clonal ramets of Salix eriostachya(+ 3.7 shrubs m-2). The frequent air temperature fluctuations had minor effect on Salix eriostachya. Based on these findings, we highlighted that Salix eriostachya could dominate in the community treeline ecotone of east Tibetan Plateau in the future climate warming scenario.
基金financially supported by the National Natural Science Foundation of China (Nos. 5170925431830013)+1 种基金the Youth Innovation Promotion Association, Chinese Academy of Sciences (No. 2020335)the Natural Science Foundation of Hubei Province (No. 2020CFB555)。
文摘Ecological restoration is one of the hot technologies for the reconstruction of eutrophic lake ecosystems in which the restoration and propagation of submerged plants is the key and difficult step. In this paper, the effect of vermiculite on the growth process of Vallisneria spiralis and sediment microenvironment were investigated, aiming to provide a theoretical basis for the application of vermiculite in aquatic ecological restoration. Results of growth indexes demonstrated that 5% and 10% vermiculite treatment groups statistically promote the growth of Vallisneria spiralis compared to the control. Meanwhile, the results of ecophysiological indexes showed that photosynthetic pigment, soluble sugar content, superoxide dismutase(SOD), and catalase(CAT) activity of 5% and 10% group were increased compared with the control while the malondialdehyde(MDA) content exhibited the opposite result(p < 0.05), which illustrated that vermiculite can improve the resistance of plants and delay the aging process of Vallisneria spiralis. In addition, result of PCA(Principal Component Analysis) demonstrated 5% and 10% group has improved the sediment physical conditions and create more ecological niche for microorganisms directly, and then promoted the growth of plants. The dissolution results showed that vermiculite can dissolve the constant and trace elements needed for plant growth. Furthermore, the addition of vermiculite increased the diversity of microorganisms in the sediments, and promoted the increase of plant growth-promoting bacteria and phosphorus-degrading bacteria. This study could provide a technique reference for the further application of vermiculite in the field of ecological restoration.
基金supported by the National Natural Science Foundation of China (No.30570113)the Research Fund for the Doctoral Program of Higher Education (No.20060335008),China
文摘The increasingly serious problem of acid rain is leading to increased potassium （K） loss from soils, and in our field investigation, we found that even congenerically relative Mosla species show different tolerance to K-deficiency. A hydroponic study was conducted on the growth of two Mosla species and their morphological, physiological and stoichiometric traits in response to limited （0.35 mmol K/L）, normal （3.25 mmol K/L） and excessive （6.50 mmol K/L） K concentrations. Mosla hangchowensis is an endangered plant, whereas Mosla dianthera a widespread weed. In the case of M. hangchowensis, in comparison with normal K concentration, K-limitation induced a significant reduction in net photosynthetic rate （Pn）, soluble protein content, and superoxide dismutase （SOD） actix, ity, but an increase in malondialdehyde （MDA） concentration. However, leaf mass ratio （LMR） and root mass ratio （RMR） were changed little by K-limitation. In contrast, for M. dianthera, K-limitation had little effect on Pn, soluble protein content, SOD activity, and MDA concentration, but increased LMR and RMR. Critical values of N （nitrogen）：K and K：P （phosphorus） ratios in the shoots indicated that limitation in acquiring K occurred under K-limited conditions for M. hangchowensis but not for M. dianthera. We found that low K content in natural habitats was a restrictive factor in the growth and distribution of M.. hangchowensis, and soil K-deficiency caused by acid rain worsened the situation of M. hangchowensis, while M. dianthera could well acclimate to the increasing K-deficiency. We suggest that controlling the acid rain and applying K fertilizers may be an effective way to rescue the endangered M. hangchowensis.
基金Scholarships to J.B.were provided by the Natural Sciences and Engineering Research Council of Canada(NSERC-CGS M)the Fonds de recherche du Québec–Nature et technologies(FRQNT)funded by the Natural Sciences and Engineering Research Council of Canada through discovery grants to M.G.andÉB。
文摘Background:Black spruce(Picea mariana(Mill.)BSP)-forested peatlands are widespread ecosystems in boreal North America in which peat accumulation,known as the paludification process,has been shown to induce forest growth decline.The continuously evolving environmental conditions(e.g.,water table rise,increasing peat thickness)in paludified forests may require tree growth mechanism adjustments over time.In this study,we investigate tree ecophysiological mechanisms along a paludification gradient in a boreal forested peatland of eastern Canada by combining peat-based and tree-ring analyses.Carbon and oxygen stable isotopes in tree rings are used to document changes in carbon assimilation rates,stomatal conductance,and water use efficiency.In addition,paleohydrological analyses are performed to evaluate the dynamical ecophysiological adjustments of black spruce trees to site-specific water table variations.Results:Increasing peat accumulation considerably impacts forest growth,but no significant differences in tree water use efficiency(iWUE)are found between the study sites.Tree-ring isotopic analysis indicates no iWUE decrease over the last 100 years,but rather an important increase at each site up to the 1980 s,before iWUE stabilized.Surprisingly,inferred basal area increments do not reflect such trends.Therefore,iWUE variations do not reflect tree ecophysiological adjustments required by changes in growing conditions.Local water table variations induce no changes in ecophysiological mechanisms,but a synchronous shift in iWUE is observed at all sites in the mid-1980 s.Conclusions:Our study shows that paludification induces black spruce growth decline without altering tree water use efficiency in boreal forested peatlands.These findings highlight that failing to account for paludification-related carbon use and allocation could result in the overestimation of aboveground biomass production in paludified sites.Further research on carbon allocation strategies is of utmost importance to understand the carbon sink capacity of these widespread ecosystems in the context of climate change,and to make appropriate forest management decisions in the boreal biome.
基金supported by the National Key Research and Development Program of China(2016YFD0300102 and 2016YFD0300105)the Key Research and Development Plan in Shaanxi Province,China(2019NY-054)the“Western Light”Visiting Scholarship Program,China。
文摘In past 30 years, the wheat yield per unit area of China has increased by 79%. The super-high-yield(SH) cultivation played an important role in improving the wheat photosynthesis and yield. In order to find the ecophysiological mechanism underneath the high photosynthesis of SH cultivation, in situ diurnal changes in the photosynthetic gas exchange and chlorophyll(Chl) a fluorescence of field-grown wheat plants during the grain-filling stage and environmental factors were investigated. During the late grain-filling stage at 24 days after anthesis(DAA), the diurnal changes in net CO_(2) assimilation rate were higher under SH treatment than under high-yield(H) treatment. From 8 to 24 DAA, the actual quantum yield of photosystem II(PSII) electron transport in the light-adapted state(ΦPSII) in the flag leaves at noon under SH treatment were significantly higher than those under H treatment. The leaf temperature, soil temperature and soil moisture were better suited for higher rates of leaf photosynthesis under SH treatment than those under H treatment at noon. Such diurnal changes in environmental factors in wheat fields could be one of the mechanisms for the higher biomass and yield under SH cultivation than those under H cultivation. ΦPSII and CO_(2) exchange rate in wheat flag leaves under SH and H treatments had a linear correlation which could provide new insight to evaluate the wheat photosynthesis performance under different conditions.
文摘Deserts have traditionally been considered as a low moisture system where biological activity is triggered by unpredictable rainfall in time and space. Studies on desert ecosystems functions, processes, dynamics and diversity of soil biota had been found to contribute to understanding of their role in primary production and management of soil ecosystems. As belowground biota is very diverse they are playing an important role in above as well below ground essential ecosystem processes e.g. primary production, decomposition, nutrient mineralization etc. The challenge is to use the emerging knowledge of soil biota diversity in understanding basic ecosystems function.
基金Supported by the National Natural Science Foundation of China(Nos.42177055,41877410)the Chongqing Postgraduate Scientifi c Research Innovation Project(Nos.CYS21106,CYS20105)。
文摘Raphidiopsis raciborskii is a notorious bloom-forming and filamentous cyanobacterium that has been extensively investigated into its toxicity,phylogeny,and spreading potential.Studies have demonstrated that this species has spanned different climates from tropical zones to temperate regions,suggesting that R.raciborskii is becoming a cosmopolitan species in freshwater systems around the world.In fact,it has been proposed that several characteristics of R.raciborskii may explain its spread and dominance.In particular,R.raciborskii is known to display a high extent of physiological plasticity regarding nutrients,light regimes,and te mperature s.Moreover,this species illustrates different ecotype s with distinct environmental requirements.Here,we present an overview of R.raciborskii’s global distribution and adaptation strategy based on the recent findings from genome variance,toxicity,and ecophysiology.The expansion of its geographical distribution can be linked to its genome,toxicity,and ecophysiology.The variable genes are mainly associated with the stress response,phage defense,DNA repair,cell cycle control,and membrane transport,illustrating the species’adaptability in response to changing environments.In fact,the species shows rapid adaptability to low and/or variable nutrient availability,especially changing phosphorus availability.Moreover,the variabilities of strains within the population extend their flexibility to adapt and acclimate to ambient environment.In addition,cylindrospermopsins(CYN)appear to have a potential biological role in facilitating theirs dominance or bloom.These strategies of R.raciborskii make it a challenge to manage in a fre shwater system,reflecting the management of its bloom from further evidence of the complex ecophysiology,toxicity,and genome of this species.
基金This work was supported by Mediterranea University of Reggio Calabria Italy as part of the Lifelong Learning Program ERASMUS Placement 2013-2014.
文摘Considering that diverse fire severities can affect soil properties differently,the aim of this study was to examine to what extent changes in soil properties caused by fire could condition seedling establishment.This new approach is for identifying a new fire cause-effect chain to qualify the impacts of fire on soils with the purpose of using fire as a tool in forest management to favour Pinus halepensis Mill.regeneration.The study area was a reforested P.halepensis area which had been crossed by fire for78.8 ha,causing various degrees of damage.The forest was subdivided into three large areas according to the gravity of crown scorch,[low(LS),medium(MS)and high(HS)severity],on the basis of needle yellowing which usually occurs after exposure to direct flames.Results showed significant differences in soil properties with respect to fire severity.In the HS area,total nitrogen and carbon were considerably reduced while ash and phosphorus contents significantly increased.The changes in soil properties,in particular to nutrient levels,affected P.halepensis regeneration,mainly the first year after the fire.Greater regeneration occurred in areas affected by moderate fire severity in which the temperatures reached increased the mineralization of soil organic matter with the consequent release of nutrients available for seedling growth.Additionally,moderate fire severity suppressed the regeneration of grasses,reducing the interspecific competition.Heights of seedlings were inversely proportional to the density of grasses.Where the number was abundant(LS),the height was modest;conversely,where the number was low(HS),the greater hypsometric differentiation of pine seedlings was observed.These results suggest that moderate fire severity represents an environmental stress(hormesis)altering microscale conditions to increase pine germination and establishment.The exposure of P.halpensis to a moderate environmental factor that is damaging at higher intensities,induces an adaptive beneficial effect on seedling regeneration.This data can re-evaluate the assertion that coniferous burned areas,if left unmanaged,would remain unproductive for an indefinite period.
基金This study was funded by the National Natural Science Foundation of China(32171746,31870522 and 31670550)Special Foundation for National Science and Technology Basic Research Program of China(2019FY101300)the Scientific Research Foundation of Henan Agricultural University(30500854).
文摘Independence among leaf economics,leaf hydraulics and leaf size confers plants great capability in adapting to heterogeneous environments.However,it remains unclear whether the independence of the leaf traits revealed across species still holds within species,especially under stressed conditions.Here,a suite of traits in these dimensions were measured in leaves and roots of a typical mangrove species,Ceriops tagal,which grows in habitats with a similar sunny and hot environment but different soil salinity in southern China.Compared with C.tagal under low soil salinity,C.tagal under high soil salinity had lower photosynthetic capacity,as indicated directly by a lower leaf nitrogen concentration and higher water use efficiency,and indirectly by a higher investment in defense function and thinner palisade tissue;had lower water transport capacity,as evidenced by thinner leaf minor veins and thinner root vessels;and also had much smaller single leaf area.Leaf economics,hydraulics and leaf size of the mangrove species appear to be coordinated as one trait dimension,which likely stemmed from covariation of soil water and nutrient availability along the salinity gradient.The intraspecific leaf trait relationship under a stressful environment is insightful for our understanding of plant adaption to the multifarious environments.
基金National Natural Science Foundation of China(grant numbers 31870427&31730014)by Jiangxi Province 2019 Graduate Innovation Fund Project(grant number YC2019-b061)。
文摘Tree competitiveness generally depends on trait plasticity in response to environmental change.The effects of nitrogen(N)and phosphorus(P)on leaf trait variability by species is poorly understood,especially in China’s subtropical forests.This study examined the seedling leaf traits and net primary productivity of all trees>5 cm DBH of two dominant species,Schima superba and Castanopsis carlesii,in an evergreen broadleaved forest fertilized with nitrogen(+N),phosphorus(+P),and nitrogen plus phosphorus(N+P).The effect of N on seedling leaf traits was stronger than P,while fertilization in general was species dependent.Leaf mass per unit area decreased with N for S.superba seedlings but not for C.carlesii.Leaf N,P,and N/P ratios changed with N addition for both species.All four N fractions of carboxylation,bioenergetics,cell wall,and other N metabolites in C.carlesii leaves responded significantly to fertilization,while only the cell wall in S.superb a leaves responded.Other leaf functional traits,including light-saturated photosynthetic rates,water,N,and P use efficiencies,chlorophyll and non structural carbohydrate contents increased with N addition in S.superb a and by P addition in C.carlesii.Canopy closure at the stand-level increased due to N.Litter biomass and relative growth rate of S.superb a was not affected by any treatments,while both for C.carlesii significantly decreased with N+P addition.Collectively,nutrient limitation may vary at a small scale among species in a subtropical forest based on their responses of seedling traits and net primary productivity to fertilization.Seedling traits are not correlated with the net primary productivity of larger trees except for N fractions,because low light conditions induced by fertilization reduces the proportion of N allocated to photosynthesis in seedlings.In addition,acclimation differences of tree species may increase the uncertainty of community succession.
