This experiments were conducted in Nanjing （118~50＂E, 32~02＂N） and Xuzhou （117~11 ＂E, 34~15＂N）, Jiangsu Province, China, to study the response of fiber quality to the N concentration of the leaf subtending bol...This experiments were conducted in Nanjing （118~50＂E, 32~02＂N） and Xuzhou （117~11 ＂E, 34~15＂N）, Jiangsu Province, China, to study the response of fiber quality to the N concentration of the leaf subtending boll in cotton （Gossypium hirsutum L.）. Results suggested that the N dilution curve of the leaf subtending boll can accurately indicate the stage- specific plant N status for fiber development. Fiber strength is likely to be the most variable fiber quality index responding to the leaf N variation which is different in cultivars. Fiber length was the most stable index among strength, length, micronaire, and elongation. There existed an optimum leaf N concentration for fiber strength development in each stage. The optimum leaf N regression curve was very close to the N dilution curve in the middle positional fruiting branches under the 240 kg N ha-1 soil N application rate.展开更多
Relative tillering rate(RTR)increased linear-ly with the increasing of leaf N concentration(NLV)has been already reported.To testwhether this relationship could be used toquantitatively explain the difference in tille...Relative tillering rate(RTR)increased linear-ly with the increasing of leaf N concentration(NLV)has been already reported.To testwhether this relationship could be used toquantitatively explain the difference in tilleringamong a wide range of N application,field ex- periments were conducted at the IRRI farm,Los Banos,Laguna,the Philippines.Two in- dica cultivars,IR 72 and IR68284H wereused.For each cultivar,12 treatments includ- ing 4 N levels(0,60,120,and 180kgN·ha)and 3 transplanting spacing(30×20,20×20,and 10×20cm)were arranged in a ran-domized split-plot design with 4 replications.The N treatments were designated as mainplots and spacings as subplots.Fourteen-day-old seedlings were transplanted with 3seedlings per hill.The subplot area was 20m~2.Nitrogen fertilizer was applied as basal,atmidtillering,and at panicle initiation in threeequal splits.P,K,and Zn were applied asbasal at normal dosage.The field was flooded.Plant samples were taken every 7-14 d from 14d after transplanting to flower展开更多
Nitrogen(N)uptake is regulated by water availability,and a water deficit can limit crop N responses by reducing N uptake and utilization.The complex and multifaceted interplay between water availability and the crop N...Nitrogen(N)uptake is regulated by water availability,and a water deficit can limit crop N responses by reducing N uptake and utilization.The complex and multifaceted interplay between water availability and the crop N response makes it difficult to predict and quantify the effect of water deficit on crop N status.The nitrogen nutrition index(NNI)has been widely used to accurately diagnose crop N status and to evaluate the effectiveness of N application.The decline of NNI under water-limiting conditions has been documented,although the underlying mechanism governing this decline is not fully understood.This study aimed to elucidate the reason for the decline of NNI under waterlimiting conditions and to provide insights into the accurate utilization of NNI for assessing crop N status under different water-N interaction treatments.Rainout shelter experiments were conducted over three growing seasons from 2018 to 2021 under different N(75 and 225 kg N ha^(-1),low N and high N)and water(120 to 510 mm,W0 to W3)co-limitation treatments.Plant N accumulation,shoot biomass(SB),plant N concentration(%N),soil nitrate-N content,actual evapotranspiration(ET_a),and yield were recorded at the stem elongation,booting,anthesis and grain filling stages.Compared to W0,W1 to W3 treatments exhibited NNI values that were greater by 10.2 to 20.5%,12.6to 24.8%,14 to 24.8%,and 16.8 to 24.8%at stem elongation,booting,anthesis,and grain filling,respectively,across the 2018-2021 seasons.This decline in NNI under water-limiting conditions stemmed from two main factors.First,reduced ET_(a) and SB led to a greater critical N concentration(%N_(c))under water-limiting conditions,which contributed to the decline in NNI primarily under high N conditions.Second,changes in plant%N played a more significant role under low N conditions.Plant N accumulation exhibited a positive allometric relationship with SB and a negative relationship with soil nitrate-N content under water-limiting conditions,indicating co-regulation by SB and the soil nitrate-N content.However,this regulation was influenced by water availability.Plant N accumulation sourced from the soil nitrate-N content reflects soil N availability.Greater soil water availability facilitated greater absorption of soil nitrate-N into the plants,leading to a positive correlation between plant N accumulation and ET_(a)across the different water-N interaction treatments.Therefore,considering the impact of soil water availability is crucial when assessing soil N availability under water-limiting conditions.The findings of this study provide valuable insights into the factors contributing to the decline in NNI among different water-N interaction treatments and can contribute to the more accurate utilization of NNI for assessing winter wheat N status.展开更多
Growing fruit trees on the slopes of rolling hills in South China was causing serious environmental problems because of heavy application of chemical fertilizers and soil erosion. Suitable sources of fertilizers and p...Growing fruit trees on the slopes of rolling hills in South China was causing serious environmental problems because of heavy application of chemical fertilizers and soil erosion. Suitable sources of fertilizers and proper rates of applications were of key importance to both crop yields and environmental protection. In this article, the impact of four fertilizers, i.e., inorganic compound fertilizer, organic compound fertilizer, pig manure compost, and peanut cake （peanut oil pressing residue）, on chestnut （Castanea mollissima Blume） growth on a slope in South China, and on the total N and total P concentrations in runoff waters have been investigated during two years of study, with an orthogonal experimental design. Results show that the organic compound fertilizer and peanut cake promote the heights of young chestnut trees compared to the control. In addition, peanut cake increases single-fruit weights and organic compound fertilizer raises single-seed weights. All the fertilizers increased the concentrations of total N and total P in runoff waters, except for organic compound fertilizer, in the first year experiment. The observed mean concentrations of total N varied from 1.6 mg/L to 3.2 mg/L and P from 0.12 mg/L to 0.22 mg/L, which were increased with the amount of fertilizer applications, with no pattern of direct proportion. On the basis of these experiment results, organic compound fertilizer at 2 kg/tree and peanut cake at 1 kg/tree are recommended to maximize chestnut growth and minimize water pollution.展开更多
Spring wheat (Triticum aestivum L. cv. Dingxi No. 8654) was treated with twoconcentrations of atmospheric CO_2 (350 and 700 μmol mol^(-1)), two levels of soil moisture(well-watered and drought) and five rates of nitr...Spring wheat (Triticum aestivum L. cv. Dingxi No. 8654) was treated with twoconcentrations of atmospheric CO_2 (350 and 700 μmol mol^(-1)), two levels of soil moisture(well-watered and drought) and five rates of nitrogen fertilizer (0, 50, 100, 150, and 200 mgkg^(-1) soil) to study the atmospheric CO_2 concentration effect on dry matter accumulation and Nuptake of spring wheat. The effects of CO_2 enrichment on the shoot and total mass depended largelyon soil nitrogen level, and the shoot and total mass increased significantly in the moderate to highN treatments but did not increase significantly in the low N treatment. Enriched CO_2 concentrationdid not increase more shoot and total mass in the drought treatment than in the well-wateredtreatment. Thus, elevated CO_2 did not ameliorate the depressive effects of drought and nitrogenstress. In addition, root mass decreased slightly and root/shoot ratio decreased significantly dueto CO_2 enrichment in no N treatment under well-watered condition. Enriched CO_2 decreased shoot Ncontent and shoot and total N uptake; but it reduced root N content and uptake slightly. Shootcritical N concentration was lower for spring wheat grown at 700 μmol mol^(-1) CO_2 than at 350μmol mol^(-1) CO_2 in both well-watered and drought treatments. The critical N concentrations were16 and 19 g kg^(-1) for the well-watered treatment and drought treatment at elevated CO_2 and 21 and26 g kg^(-1) at ambient CO_2, respectively. The reductions in the movement of nutrients to theplant roots through mass flow due to the enhancement in WUE (water use efficiency) and the increasein N use efficiency at elevated CO_2 could elucidate the reduction of shoot and root Nconcentrations.展开更多
Better understanding of the factors that influence crop nitrogen(N) requirement plays an important role in improving regional N recommendations for rice(Oryza sativa L.) production. We collected data from 1 280 plot-l...Better understanding of the factors that influence crop nitrogen(N) requirement plays an important role in improving regional N recommendations for rice(Oryza sativa L.) production. We collected data from 1 280 plot-level measurements in different reaches of the Yangtze River, China to determine which factors contributed to variability in N requirement in rice. Yield, variety, and cropping system were significantly related to N requirement. The N requirement remained consistent at about 18.6 kg N Mg^(-1)grain as grain yield increased from 7 to 9 Mg ha^(-1), then decreased to 18.1, 16.9, and 15.9 kg N Mg^(-1)grain as yield increased to 9–10, 10–11, and > 11 Mg ha^(-1), respectively. The decreased requirement for N with increasing yield was attributable to declining N concentrations in grain and straw and increased harvest index. Super rice variety had lower N requirement(17.7 kg N Mg^(-1)grain) than ordinary inbred and hybrid varieties(18.5 and 18.3 kg N Mg^(-1)grain, respectively), which was a result of lower grain and straw N concentrations of super rice. The N requirements were 19.2, 17.8, and 17.5 kg N Mg^(-1)grain for early, middle, and late rice cropping systems, respectively. In conclusion, the rice N requirement was affected by multiple factors, including yield, variety, and cropping system, all of which should be considered when planning for optimal N management.展开更多
Short basal internodes are important for lodging resistance of rice(Oryza sativa L.).Several canopy indices affect the elongation of basal internodes,but uncertainty as to the key factors determining elongation of bas...Short basal internodes are important for lodging resistance of rice(Oryza sativa L.).Several canopy indices affect the elongation of basal internodes,but uncertainty as to the key factors determining elongation of basal internodes persists.The objectives of this study were(1)to identify key factors affecting the elongation of basal internodes and(2)to establish a quantitative relationship between basal internode length and canopy indices.An inbred rice cultivar,Yinjingruanzhan,was grown in two split-plot field experiments with three N rates(0,75,and 150 kg N ha−1 in early season and 0,90,and 180 kg N ha−1 in late season)as main plots,three seedling densities(16.7,75.0,and 187.5 seedlings m−2)as subplots,and three replications in the 2015 early and late seasons in Guangzhou,China.Light intensity at base of canopy(Lb),light quality as determined from red/far-red light ratio(R/FR),light transmission ratio(LTR),leaf area index(LAI),leaf N concentration(NLV)and final length of second internode(counted from soil surface upward)(FIL)were recorded.Higher N rate and seedling density resulted in significantly longer FIL.FIL was negatively correlated with Lb,LTR,and R/FR(P<0.01)and positively correlated with LAI(P<0.01),but not correlated with NLV(P>0.05).Stepwise linear regression analysis showed that FIL was strongly associated with Lb and LAI(R2=0.82).Heavy N application to pot-grown rice at the beginning of first internode elongation did not change FIL.We conclude that FIL is determined mainly by Lb and LAI at jointing stage.NLV has no direct effect on the elongation of basal internodes.N application indirectly affects FIL by changing LAI and light conditions in the rice canopy.Reducing LAI and improving canopy light transmission at jointing stage can shorten the basal internodes and increase the lodging resistance of rice.展开更多
Soil temperature is a major effective factor on the soil and plant biological properties.Irrigation can affect soil temperature and thereby induces a temperature effect on plant growth,which may result in an economic ...Soil temperature is a major effective factor on the soil and plant biological properties.Irrigation can affect soil temperature and thereby induces a temperature effect on plant growth,which may result in an economic increase due to higher yield and plant nutrition.A ?eld experiment was carried out to investigate the effects of three irrigation strategies including full irrigation(FI),partial root-zone drying(PRD) and de?cit irrigation(DI) on soil temperature and the consequent results on the grain yield and N uptake of maize(Zea May L.).Soil temperature was measured by time domain re?ectometry(TDR) sensors during the 2010 growing season.Irrigation treatments were applied from 55 to 107 d after planting.The PRD treatment caused soil temperature to be in a favorable domain for a longer period(for over 60% of the measuring dates) as a consequent result of water movement to deeper soil layers compared with the other treatments;the PRD treatment also reduced soil temperature at deeper soil depths to below the maximum favorable soil temperature for maize root growth,which resulted in deeper root penetration due to both water availability and favorable soil temperature.Compared to the FI treatment,the PRD treatment increased root water uptake by 50% and caused no signi?cant reduction in total N uptake,while this was not observed in the DI treatment partially due to the negative temperature effect of DI on plant growth,which consequently affected the water and nutrient uptake.A longer vegetation period in the PRD treatment was observed due to higher leaf N concentrations and no signi?cant reduction in maize grain yield occurred in the PRD treatment,compared with those in the FI treatment.Based on the results,having 15.2% water saving during the whole growing season,the PRD irrigation would positively affect soil temperature and the water and nutrient uptake as a consequent,which thereby would prevent signi?cant reduction in maize grain yield.展开更多
Eutrophication, which is the enrichment of a water mass with inorganic and organic nutrients that support plant growth, is a key factor in stimulating phytoplankton growth. In this study, we determined the effects of ...Eutrophication, which is the enrichment of a water mass with inorganic and organic nutrients that support plant growth, is a key factor in stimulating phytoplankton growth. In this study, we determined the effects of various nitrogen sources, different nitrogen concentrations in the culture medium, and two culture methods on the growth of the green alga, Enteromorpha prolifera. The relationship between the specific growth rate of E. prolifera and NO3-N concentration was consistent with that estimated using the Monod equation （R2=0.9713, P〈0.01）. In the N O3-N medium, the maximum specific growth rate was calculated to be 0.1634/d and the semi-saturation constant was calculated to be 16.86 μmol/L. Our results show that E. prolijkra can effectively utilize NH4^＋-N, NO3^-N, and NO^2-N and urea-N in the range of 5 to 50 μmol/L. NH4^＋-N was preferentially assimilated by E. prolifera, and urea-N was favorable for long-term growth.展开更多
A generalized, lumped-parameter ecological model PnET-CN was calibrated and validated for a subtropical coniferous plantation in southern China. PnET-CN model describes the biogeochemical cycles of carbon （C） and ni...A generalized, lumped-parameter ecological model PnET-CN was calibrated and validated for a subtropical coniferous plantation in southern China. PnET-CN model describes the biogeochemical cycles of carbon （C） and nitrogen （N） and can assist in estimating carbon sequestration potential. For validation of PnET-CN, data from coniferous forest plantations in southern China was used. Simulated daily gross primary productivity （GPP） from 2005 to 2007 agreed well with observations （R2=0.56, S.D.=0.009）. Simulations of monthly soil respiration （Rs） from 2005-2007 agreed well with Rs observations （R2=0.67, S.D. =0.03）. Simu- lated annual net primary productivity （NPP） from 1998-2006 was 803＋33 gCm 2a-1, about 4% higher than NPP observation （752＋51 gCm-2a-1）. Simulations of annual NEP from 2005-2007 only overestimate 9 gCm-2a-1 （4%）, 4 gCm 2a-1 （1%） and 34 gCm 2a-1 （8%） compared to NEP observations, respectively. Simulated annual foliar N concentration （FolNCon） （1.09%） is 10% lower than observed monthly FolNCon （0.87%-1.58%）. Simulated annual N leaching （0.26 gNm-2） is about 10% lower than leaching observation （0.29 gNm-2）. PnET-CN model validation indicates that PnET-CN is capable to simulate daily GPP, annual NPP, annual NEP, monthly Rs, annual FolNCon and annual nitrate N leaching for subtropical coniferous planta- tions in southern China. The results obtained from the validation test revealed that PnET-CN model can be used to simulate carbon sequestration of planted coniferous forests in southern China to a high level of precision. Sensitivity analysis suggests that great care should be taken in developing generalizations as to how forests will respond to a changing climate. PnET-CN performed satisfactorily in comparison to other models that have already been calibrated and validated in coniferous planted subtropical forests in China. Based on PnET-CN validation and its comparison to other models, future improvement of PnET-CN should focus on seasonal foliar N dynamics and the effects of water stress on autotrophic respirations in subtropical coniferous plantations in southern China.展开更多
The present study was undertaken in Forest Science Faculty, Universidad de Nuevo Leon, Mexico on variability of Wood density and its possible relation to few wood chemical composition and wood fiber cell structure ana...The present study was undertaken in Forest Science Faculty, Universidad de Nuevo Leon, Mexico on variability of Wood density and its possible relation to few wood chemical composition and wood fiber cell structure anatomy. The results reveal that among 10 specie studied, there exist a large variation in wood density (0.51 to 1.09), and few wood chemical composition such % carbón (37.14 to 44.07), nitrogen (9.18 to 19.22), sulphur (31.45 to 33/82), lignin (15/28 to 24.35), hemicellulose (19.94 to 27.36%), and % cellulose (33.69 to 45.92). In general, though there was no clear relationship between wood density and other chemical composition of wood. It was observed that the species having moderate to high wood density contained >40% carbón, >30% sulphur and >40% cellulose and more or less 20% lignin. It seems that carbón, sulphur, cellulose and lignin content contribute to greater density. The wood fiber cell with wall lignification seems to be related to higher wood density.展开更多
Leaf N and P stoichiometry in terrestrial ecosystems has been widely investigated in recent years owing to the importance of these elements in improving the predicted vegetation responses to global changes.The vertica...Leaf N and P stoichiometry in terrestrial ecosystems has been widely investigated in recent years owing to the importance of these elements in improving the predicted vegetation responses to global changes.The vertical distribution of leaf N and P stoichiometry has attracted increasing attention because of the dramatic changes in environmental factors at regional scales.However,the characteristics of leaf N and P stoichiometry in the southeast Qinghai–Tibet plateau(SET)are not clear,although this area is sensitive to global change.Here,we analyzed the leaf N and P concentrations in dominant plant species on natural altitudinal gradients on the Duoxiongla(DXL),Sejila(SJL),Mila(ML),and Gangbala(GBL)mountains across the SET all the way to central Tibet.Our results showed that the leaf N concentrations were comparable among the regions,whereas the leaf P concentrations dramatically decreased from SET to central Tibet(CT).The leaf N concentrations were 23.6,21.3,20.8,and 22.4 g kg^(-1),and the leaf P concentrations were 2.40,2.49,1.94,and 1.59 g kg^(-1)on the SJL,DXL,ML and GBL mountains,respectively.The leaf N/P ratios on the DXL,SJL,ML,and GBL mountains were 8.81,10.3,11.2,and 14.2,respectively.Considering the increasing trend of the leaf N/P ratio from southeast Qinghai–Tibet plateau to central Tibet,N limitation might widely exist in well vegetated ecosystems in the Qinghai–Tibet plateau.展开更多
The objective of this paper relies on the establishment of the sampling moment and the nutritional state of the species Conilon coffee （Coffea canephora） cultivated in Cambisoils. The effect of different rates of ni...The objective of this paper relies on the establishment of the sampling moment and the nutritional state of the species Conilon coffee （Coffea canephora） cultivated in Cambisoils. The effect of different rates of nitrogen fertilization was also studied in the leaves concentrations of N, at randomized complete block designs （N0= 0; N1 = 50; N2 = 100; N3 = 150 and N4 = 200 kg.ha^-1 of N） in presence of P （40 kg.ha^-1 of P2O5） and K （160 kg.ha^-1 of K2O）, with four replicates. The samples were carried out in the months of March （flower blossoming stage）, June （fruits growing stage）, September （grain development） and December （maturation） in all treatments. Foliar analysis carried out in the month of June （fruits growing stage） for the purpose of establishing critical nutrient range values for N, settling down approaches of interpretation of the same one for the Conilon coffee plantations on Cambisoils. The biggest percentages in the yields are obtained with leaves containing N between 2.80% and 3.10%, a value below 2.80% N which they associated with indicative percentages of stable maximum yield that did not surpass the limits of the adequate nutrients supply.展开更多
Aims Recent work has identified a worldwide‘economics’spectrum of correlated leaf traits that mainly reflects the compromises between maximizing leaf longevity and short-term productivity.However,during the early st...Aims Recent work has identified a worldwide‘economics’spectrum of correlated leaf traits that mainly reflects the compromises between maximizing leaf longevity and short-term productivity.However,during the early stages of tree growth different species tend to exhibit a common strategy,because competition for soil water and nutrients forces the maximization of short-term productivity owing to the need for rapid growth during the most vulnerable part of the tree’s life cycle.Accordingly,our aim here was to compare the variations that occur during ontogeny in the different leaf traits(morphology and leaf chemical composition)of several coexisting Mediterranean woody species differing in their leaf life spans and to test our hypothesis that tree species with a long leaf life span should exhibit larger shifts in leaf characteristics along ontogeny.Methods Six Mediterranean tree species differing in leaf life span,selected from three plots located in central-western Spain,were studied during three growth stages:seedlings,juveniles and mature trees.Leaf life span,leaf morphology(leaf area,dry weight,thickness and mass per unit area)and chemical composition(N and fibre con-centrations)were measured in all six species.The magnitude of the ontogenetic changes in the different traits was estimated and related to the mean leaf longevity of the different species.Important Findings Along ontogeny,strong changes were observed in all variables analysed.The early growth stages showed lower leaf thickness,leaf thickness and mass per unit area and N,cellulose and hemi-cellulose concentrations than mature trees,but a higher lignin content.However,these changes were especially marked in species with a longer leaf life span at maturity.Interspecific dif-ferences in leaf life span,leaf morphology and chemical com-position were stronger at the mature stage than at the seedling stage.We conclude that greater plasticity and more intense strat-egy shifts along ontogeny are necessarily associated with long leaf life span.Our results thus provide a new aspect that should be incorporated into the analysis of the costs and benefits associ-ated with the different strategies related to leaf persistence dis-played by the different species.Accordingly,the intensity of the alterations in leaf traits among different growth stages should be added to the suite of traits that change along the leaf economics spectrum.展开更多
Background:Increasing atmospheric[CO_(2)]can increase photosynthesis and promote plant growth,consequently influencing nitrogen(N)cycling.Yet,there is no systematic information on the N response among different organs...Background:Increasing atmospheric[CO_(2)]can increase photosynthesis and promote plant growth,consequently influencing nitrogen(N)cycling.Yet,there is no systematic information on the N response among different organs of japonica and indica rice genotypes to elevated[CO_(2)]as affected by N application.To investigate the impacts of elevated[CO_(2)]and N fertilization on N uptake and utilization of different genotypic rice(Oryza sativa L.)during grain filling,a free-air CO_(2) enrichment(FACE)experiment with indica cv.Liangyou 084(IIY084)and japonica cv.Wuyunjing 23(WYJ23)was conducted in Eastern China.Crops were exposed to ambient[CO_(2)]and elevated[CO_(2)](200μmol mol^(−1) above ambient)at two levels of N:control(0N)and 22.5 g N m^(−2)(normal N,NN),and they were sampled at 82 days after transplanting(DAT),99 DAT,and maturity,respectively.Results:Under FACE,significant declines of N concentration in all tissues and the whole plants were observed with the greater decrease in leaves and stems at three stages.Positive responses of N use efficiency(NUE)to elevated[CO_(2)]were recorded over the study period.The total N accumulation remained unchanged,while a large amount of N was partitioned to panicles at the expense of leaves and stems.As compared to WYJ23,greater N transportation from roots to aboveground,especially the panicles,was observed on IIY084 accompanied by higher panicle biomass(82 DAT and 99 DAT),N concentrations(maturity),and greater NUE for leaves through the study season.Across all[CO_(2)]and cultivars,N fertilization increased N partitioning to leaves and stems while decreasing that to panicles.Additionally,N supply decreased NUE while stimulating N concentrations and N amounts of rice plants.Among all treatments,IIY084 had the highest N accumulation and allocation in panicles under elevated[CO_(2)]in combination with N fertilizer at maturity.Conclusion:Data from this study were helpful for understanding the temporal N uptake and utilization of different rice genotypes as affected by N availability and suggest that IIY084 promises a considerable prospect for its grain yield and quality under future elevated atmospheric[CO_(2)].展开更多
The objective of this paper was to assess the congruency of leaf traits and soil characteristics and to analyze the survival strategies of different plant functional types in response to drought and nutrient-poor envi...The objective of this paper was to assess the congruency of leaf traits and soil characteristics and to analyze the survival strategies of different plant functional types in response to drought and nutrient-poor environ-ments in the southeastern Ke’erqin Sandy Lands in China.Six leaf traits—leaf thickness(TH),density(DN),specific leaf area(SLA),leaf dry weight to fresh weight ratio(DW/FW),leaf N concentration(N mass),and N resorption efficiency(NRE_(mass))-of 42 plant species were investi-gated at four sites.The correlations between leaf traits and soil characteristics-organic C(OC),total N(TN),total P(TP),and soil moisture(SM)-were examined.We found that the six leaf traits across all the 42 species showed large variations and that DW/FW was negatively correlated with OC,TN,TP,and SM(P<0.05),while other leaf traits showed no significant correlations with soil characteristics.To find the dissimilarity to accommodate environment,a hierarchical agglomerative clustering analysis was made of all the species.All the species clustered into three groups except the Scutellaria baicalensis.Species of group III might be most tolerant of an arid environment,and species of group II might avoid nutrient stress in the nutrient-poor environment,while group I was somewhat intermediate.Therefore,species from the different groups may be selected for use in vegetation restoration of different sites based on soil moisture and nutrient conditions.展开更多
基金funded by the National Natural Science Foundation of China(30771279)the Specialized Research Funds for the Doctoral Program of Higher Education,China(20080307001)
文摘This experiments were conducted in Nanjing （118~50＂E, 32~02＂N） and Xuzhou （117~11 ＂E, 34~15＂N）, Jiangsu Province, China, to study the response of fiber quality to the N concentration of the leaf subtending boll in cotton （Gossypium hirsutum L.）. Results suggested that the N dilution curve of the leaf subtending boll can accurately indicate the stage- specific plant N status for fiber development. Fiber strength is likely to be the most variable fiber quality index responding to the leaf N variation which is different in cultivars. Fiber length was the most stable index among strength, length, micronaire, and elongation. There existed an optimum leaf N concentration for fiber strength development in each stage. The optimum leaf N regression curve was very close to the N dilution curve in the middle positional fruiting branches under the 240 kg N ha-1 soil N application rate.
文摘Relative tillering rate(RTR)increased linear-ly with the increasing of leaf N concentration(NLV)has been already reported.To testwhether this relationship could be used toquantitatively explain the difference in tilleringamong a wide range of N application,field ex- periments were conducted at the IRRI farm,Los Banos,Laguna,the Philippines.Two in- dica cultivars,IR 72 and IR68284H wereused.For each cultivar,12 treatments includ- ing 4 N levels(0,60,120,and 180kgN·ha)and 3 transplanting spacing(30×20,20×20,and 10×20cm)were arranged in a ran-domized split-plot design with 4 replications.The N treatments were designated as mainplots and spacings as subplots.Fourteen-day-old seedlings were transplanted with 3seedlings per hill.The subplot area was 20m~2.Nitrogen fertilizer was applied as basal,atmidtillering,and at panicle initiation in threeequal splits.P,K,and Zn were applied asbasal at normal dosage.The field was flooded.Plant samples were taken every 7-14 d from 14d after transplanting to flower
基金supported by the National Natural Science Foundation of China(51609247)the Henan Provincial Natural Science Foundation,China(222300420589,202300410553)+4 种基金the Central Public-interest Scientific Institution Basal Research Fund,China(FIRI2022-22)the Science&Technology Fundamental Resources Investigation Program,China(2022FY101601)the Science and Technology Project of Xinxiang City,Henan Province,China(GG2021024)the Major Special Science and Technology Project of Henan Province,China(221100110700)the Joint Fund of Science and Technology Research and Development Plan of Henan Province,China(Superior Discipline Cultivation)(222301420104)。
文摘Nitrogen(N)uptake is regulated by water availability,and a water deficit can limit crop N responses by reducing N uptake and utilization.The complex and multifaceted interplay between water availability and the crop N response makes it difficult to predict and quantify the effect of water deficit on crop N status.The nitrogen nutrition index(NNI)has been widely used to accurately diagnose crop N status and to evaluate the effectiveness of N application.The decline of NNI under water-limiting conditions has been documented,although the underlying mechanism governing this decline is not fully understood.This study aimed to elucidate the reason for the decline of NNI under waterlimiting conditions and to provide insights into the accurate utilization of NNI for assessing crop N status under different water-N interaction treatments.Rainout shelter experiments were conducted over three growing seasons from 2018 to 2021 under different N(75 and 225 kg N ha^(-1),low N and high N)and water(120 to 510 mm,W0 to W3)co-limitation treatments.Plant N accumulation,shoot biomass(SB),plant N concentration(%N),soil nitrate-N content,actual evapotranspiration(ET_a),and yield were recorded at the stem elongation,booting,anthesis and grain filling stages.Compared to W0,W1 to W3 treatments exhibited NNI values that were greater by 10.2 to 20.5%,12.6to 24.8%,14 to 24.8%,and 16.8 to 24.8%at stem elongation,booting,anthesis,and grain filling,respectively,across the 2018-2021 seasons.This decline in NNI under water-limiting conditions stemmed from two main factors.First,reduced ET_(a) and SB led to a greater critical N concentration(%N_(c))under water-limiting conditions,which contributed to the decline in NNI primarily under high N conditions.Second,changes in plant%N played a more significant role under low N conditions.Plant N accumulation exhibited a positive allometric relationship with SB and a negative relationship with soil nitrate-N content under water-limiting conditions,indicating co-regulation by SB and the soil nitrate-N content.However,this regulation was influenced by water availability.Plant N accumulation sourced from the soil nitrate-N content reflects soil N availability.Greater soil water availability facilitated greater absorption of soil nitrate-N into the plants,leading to a positive correlation between plant N accumulation and ET_(a)across the different water-N interaction treatments.Therefore,considering the impact of soil water availability is crucial when assessing soil N availability under water-limiting conditions.The findings of this study provide valuable insights into the factors contributing to the decline in NNI among different water-N interaction treatments and can contribute to the more accurate utilization of NNI for assessing winter wheat N status.
基金Project supported by the Science and Technology Department of Guang-dong Province (No: 2004B33301007)the Rockefeller Brothers Fund
文摘Growing fruit trees on the slopes of rolling hills in South China was causing serious environmental problems because of heavy application of chemical fertilizers and soil erosion. Suitable sources of fertilizers and proper rates of applications were of key importance to both crop yields and environmental protection. In this article, the impact of four fertilizers, i.e., inorganic compound fertilizer, organic compound fertilizer, pig manure compost, and peanut cake （peanut oil pressing residue）, on chestnut （Castanea mollissima Blume） growth on a slope in South China, and on the total N and total P concentrations in runoff waters have been investigated during two years of study, with an orthogonal experimental design. Results show that the organic compound fertilizer and peanut cake promote the heights of young chestnut trees compared to the control. In addition, peanut cake increases single-fruit weights and organic compound fertilizer raises single-seed weights. All the fertilizers increased the concentrations of total N and total P in runoff waters, except for organic compound fertilizer, in the first year experiment. The observed mean concentrations of total N varied from 1.6 mg/L to 3.2 mg/L and P from 0.12 mg/L to 0.22 mg/L, which were increased with the amount of fertilizer applications, with no pattern of direct proportion. On the basis of these experiment results, organic compound fertilizer at 2 kg/tree and peanut cake at 1 kg/tree are recommended to maximize chestnut growth and minimize water pollution.
基金the National Key Basic Research Support Foundation(NKBRSF)of China(No.G1999011708) the Guangxi University Science funds,China(No.1701).
文摘Spring wheat (Triticum aestivum L. cv. Dingxi No. 8654) was treated with twoconcentrations of atmospheric CO_2 (350 and 700 μmol mol^(-1)), two levels of soil moisture(well-watered and drought) and five rates of nitrogen fertilizer (0, 50, 100, 150, and 200 mgkg^(-1) soil) to study the atmospheric CO_2 concentration effect on dry matter accumulation and Nuptake of spring wheat. The effects of CO_2 enrichment on the shoot and total mass depended largelyon soil nitrogen level, and the shoot and total mass increased significantly in the moderate to highN treatments but did not increase significantly in the low N treatment. Enriched CO_2 concentrationdid not increase more shoot and total mass in the drought treatment than in the well-wateredtreatment. Thus, elevated CO_2 did not ameliorate the depressive effects of drought and nitrogenstress. In addition, root mass decreased slightly and root/shoot ratio decreased significantly dueto CO_2 enrichment in no N treatment under well-watered condition. Enriched CO_2 decreased shoot Ncontent and shoot and total N uptake; but it reduced root N content and uptake slightly. Shootcritical N concentration was lower for spring wheat grown at 700 μmol mol^(-1) CO_2 than at 350μmol mol^(-1) CO_2 in both well-watered and drought treatments. The critical N concentrations were16 and 19 g kg^(-1) for the well-watered treatment and drought treatment at elevated CO_2 and 21 and26 g kg^(-1) at ambient CO_2, respectively. The reductions in the movement of nutrients to theplant roots through mass flow due to the enhancement in WUE (water use efficiency) and the increasein N use efficiency at elevated CO_2 could elucidate the reduction of shoot and root Nconcentrations.
基金supported by the Special Fund for Agro-scientific Research in the Public Interest, China (No. 201303103)the National Key Research and Development Program, China (No. 2016YFD0200105)the Innovative Group Grant of the National Natural Science Foundation of China (No. 31121062)
文摘Better understanding of the factors that influence crop nitrogen(N) requirement plays an important role in improving regional N recommendations for rice(Oryza sativa L.) production. We collected data from 1 280 plot-level measurements in different reaches of the Yangtze River, China to determine which factors contributed to variability in N requirement in rice. Yield, variety, and cropping system were significantly related to N requirement. The N requirement remained consistent at about 18.6 kg N Mg^(-1)grain as grain yield increased from 7 to 9 Mg ha^(-1), then decreased to 18.1, 16.9, and 15.9 kg N Mg^(-1)grain as yield increased to 9–10, 10–11, and > 11 Mg ha^(-1), respectively. The decreased requirement for N with increasing yield was attributable to declining N concentrations in grain and straw and increased harvest index. Super rice variety had lower N requirement(17.7 kg N Mg^(-1)grain) than ordinary inbred and hybrid varieties(18.5 and 18.3 kg N Mg^(-1)grain, respectively), which was a result of lower grain and straw N concentrations of super rice. The N requirements were 19.2, 17.8, and 17.5 kg N Mg^(-1)grain for early, middle, and late rice cropping systems, respectively. In conclusion, the rice N requirement was affected by multiple factors, including yield, variety, and cropping system, all of which should be considered when planning for optimal N management.
基金supported by the Natural Science Foundation of Guangdong Province,China(S2012020011043)the National High Technology Research and Development Program of China(2014AA10A605)+2 种基金the Special Fund for Agro-scientific Research in the Public Interest(201503106)Modern Agriculture Industry Technology System for Rice in Guangdong Province(2016LM1066,2017LM1066,2018LM1066)the Swiss Agency for Development and Cooperation through its funding of “Closing Rice Yield Gaps in Asia” Project(CORIGAP)
文摘Short basal internodes are important for lodging resistance of rice(Oryza sativa L.).Several canopy indices affect the elongation of basal internodes,but uncertainty as to the key factors determining elongation of basal internodes persists.The objectives of this study were(1)to identify key factors affecting the elongation of basal internodes and(2)to establish a quantitative relationship between basal internode length and canopy indices.An inbred rice cultivar,Yinjingruanzhan,was grown in two split-plot field experiments with three N rates(0,75,and 150 kg N ha−1 in early season and 0,90,and 180 kg N ha−1 in late season)as main plots,three seedling densities(16.7,75.0,and 187.5 seedlings m−2)as subplots,and three replications in the 2015 early and late seasons in Guangzhou,China.Light intensity at base of canopy(Lb),light quality as determined from red/far-red light ratio(R/FR),light transmission ratio(LTR),leaf area index(LAI),leaf N concentration(NLV)and final length of second internode(counted from soil surface upward)(FIL)were recorded.Higher N rate and seedling density resulted in significantly longer FIL.FIL was negatively correlated with Lb,LTR,and R/FR(P<0.01)and positively correlated with LAI(P<0.01),but not correlated with NLV(P>0.05).Stepwise linear regression analysis showed that FIL was strongly associated with Lb and LAI(R2=0.82).Heavy N application to pot-grown rice at the beginning of first internode elongation did not change FIL.We conclude that FIL is determined mainly by Lb and LAI at jointing stage.NLV has no direct effect on the elongation of basal internodes.N application indirectly affects FIL by changing LAI and light conditions in the rice canopy.Reducing LAI and improving canopy light transmission at jointing stage can shorten the basal internodes and increase the lodging resistance of rice.
基金Sari Agricultural Sciences and Natural Resources University(SANRU),Iran for giving the site for field investigation and to appreciate University of Zabol for financial support of this research
文摘Soil temperature is a major effective factor on the soil and plant biological properties.Irrigation can affect soil temperature and thereby induces a temperature effect on plant growth,which may result in an economic increase due to higher yield and plant nutrition.A ?eld experiment was carried out to investigate the effects of three irrigation strategies including full irrigation(FI),partial root-zone drying(PRD) and de?cit irrigation(DI) on soil temperature and the consequent results on the grain yield and N uptake of maize(Zea May L.).Soil temperature was measured by time domain re?ectometry(TDR) sensors during the 2010 growing season.Irrigation treatments were applied from 55 to 107 d after planting.The PRD treatment caused soil temperature to be in a favorable domain for a longer period(for over 60% of the measuring dates) as a consequent result of water movement to deeper soil layers compared with the other treatments;the PRD treatment also reduced soil temperature at deeper soil depths to below the maximum favorable soil temperature for maize root growth,which resulted in deeper root penetration due to both water availability and favorable soil temperature.Compared to the FI treatment,the PRD treatment increased root water uptake by 50% and caused no signi?cant reduction in total N uptake,while this was not observed in the DI treatment partially due to the negative temperature effect of DI on plant growth,which consequently affected the water and nutrient uptake.A longer vegetation period in the PRD treatment was observed due to higher leaf N concentrations and no signi?cant reduction in maize grain yield occurred in the PRD treatment,compared with those in the FI treatment.Based on the results,having 15.2% water saving during the whole growing season,the PRD irrigation would positively affect soil temperature and the water and nutrient uptake as a consequent,which thereby would prevent signi?cant reduction in maize grain yield.
基金Supported by the Major Projects of Knowledge Innovation Program of Chinese Academy of Sciences (No. KZCX2-SW-208-01)the National Natural Science Foundation of China (No. 40976047)National Basic Research Program of China (973 Program) (No. 2010CB428701)
文摘Eutrophication, which is the enrichment of a water mass with inorganic and organic nutrients that support plant growth, is a key factor in stimulating phytoplankton growth. In this study, we determined the effects of various nitrogen sources, different nitrogen concentrations in the culture medium, and two culture methods on the growth of the green alga, Enteromorpha prolifera. The relationship between the specific growth rate of E. prolifera and NO3-N concentration was consistent with that estimated using the Monod equation （R2=0.9713, P〈0.01）. In the N O3-N medium, the maximum specific growth rate was calculated to be 0.1634/d and the semi-saturation constant was calculated to be 16.86 μmol/L. Our results show that E. prolijkra can effectively utilize NH4^＋-N, NO3^-N, and NO^2-N and urea-N in the range of 5 to 50 μmol/L. NH4^＋-N was preferentially assimilated by E. prolifera, and urea-N was favorable for long-term growth.
基金National Natural Science Foundation of China, No.31070438 The Key Project of CAS Knowledge Innovation Program, No.KZCX2-YW-305-3+1 种基金 No.KZCX2-YW-QN301 State Key Basic Research Development Proiect, No.2010CB833503
文摘A generalized, lumped-parameter ecological model PnET-CN was calibrated and validated for a subtropical coniferous plantation in southern China. PnET-CN model describes the biogeochemical cycles of carbon （C） and nitrogen （N） and can assist in estimating carbon sequestration potential. For validation of PnET-CN, data from coniferous forest plantations in southern China was used. Simulated daily gross primary productivity （GPP） from 2005 to 2007 agreed well with observations （R2=0.56, S.D.=0.009）. Simulations of monthly soil respiration （Rs） from 2005-2007 agreed well with Rs observations （R2=0.67, S.D. =0.03）. Simu- lated annual net primary productivity （NPP） from 1998-2006 was 803＋33 gCm 2a-1, about 4% higher than NPP observation （752＋51 gCm-2a-1）. Simulations of annual NEP from 2005-2007 only overestimate 9 gCm-2a-1 （4%）, 4 gCm 2a-1 （1%） and 34 gCm 2a-1 （8%） compared to NEP observations, respectively. Simulated annual foliar N concentration （FolNCon） （1.09%） is 10% lower than observed monthly FolNCon （0.87%-1.58%）. Simulated annual N leaching （0.26 gNm-2） is about 10% lower than leaching observation （0.29 gNm-2）. PnET-CN model validation indicates that PnET-CN is capable to simulate daily GPP, annual NPP, annual NEP, monthly Rs, annual FolNCon and annual nitrate N leaching for subtropical coniferous planta- tions in southern China. The results obtained from the validation test revealed that PnET-CN model can be used to simulate carbon sequestration of planted coniferous forests in southern China to a high level of precision. Sensitivity analysis suggests that great care should be taken in developing generalizations as to how forests will respond to a changing climate. PnET-CN performed satisfactorily in comparison to other models that have already been calibrated and validated in coniferous planted subtropical forests in China. Based on PnET-CN validation and its comparison to other models, future improvement of PnET-CN should focus on seasonal foliar N dynamics and the effects of water stress on autotrophic respirations in subtropical coniferous plantations in southern China.
文摘The present study was undertaken in Forest Science Faculty, Universidad de Nuevo Leon, Mexico on variability of Wood density and its possible relation to few wood chemical composition and wood fiber cell structure anatomy. The results reveal that among 10 specie studied, there exist a large variation in wood density (0.51 to 1.09), and few wood chemical composition such % carbón (37.14 to 44.07), nitrogen (9.18 to 19.22), sulphur (31.45 to 33/82), lignin (15/28 to 24.35), hemicellulose (19.94 to 27.36%), and % cellulose (33.69 to 45.92). In general, though there was no clear relationship between wood density and other chemical composition of wood. It was observed that the species having moderate to high wood density contained >40% carbón, >30% sulphur and >40% cellulose and more or less 20% lignin. It seems that carbón, sulphur, cellulose and lignin content contribute to greater density. The wood fiber cell with wall lignification seems to be related to higher wood density.
基金funded by the Natural Science Foundation of Tibet Autonomous Region Department and Agriculture and Animal Husbandry University(XZ202101ZR0023G)the National Natural Science Foundation of China(42067036)the Forestry Innovation Team Construction project of Xizang Agriculture and Animal Husbandry University(2020-001)。
文摘Leaf N and P stoichiometry in terrestrial ecosystems has been widely investigated in recent years owing to the importance of these elements in improving the predicted vegetation responses to global changes.The vertical distribution of leaf N and P stoichiometry has attracted increasing attention because of the dramatic changes in environmental factors at regional scales.However,the characteristics of leaf N and P stoichiometry in the southeast Qinghai–Tibet plateau(SET)are not clear,although this area is sensitive to global change.Here,we analyzed the leaf N and P concentrations in dominant plant species on natural altitudinal gradients on the Duoxiongla(DXL),Sejila(SJL),Mila(ML),and Gangbala(GBL)mountains across the SET all the way to central Tibet.Our results showed that the leaf N concentrations were comparable among the regions,whereas the leaf P concentrations dramatically decreased from SET to central Tibet(CT).The leaf N concentrations were 23.6,21.3,20.8,and 22.4 g kg^(-1),and the leaf P concentrations were 2.40,2.49,1.94,and 1.59 g kg^(-1)on the SJL,DXL,ML and GBL mountains,respectively.The leaf N/P ratios on the DXL,SJL,ML,and GBL mountains were 8.81,10.3,11.2,and 14.2,respectively.Considering the increasing trend of the leaf N/P ratio from southeast Qinghai–Tibet plateau to central Tibet,N limitation might widely exist in well vegetated ecosystems in the Qinghai–Tibet plateau.
文摘The objective of this paper relies on the establishment of the sampling moment and the nutritional state of the species Conilon coffee （Coffea canephora） cultivated in Cambisoils. The effect of different rates of nitrogen fertilization was also studied in the leaves concentrations of N, at randomized complete block designs （N0= 0; N1 = 50; N2 = 100; N3 = 150 and N4 = 200 kg.ha^-1 of N） in presence of P （40 kg.ha^-1 of P2O5） and K （160 kg.ha^-1 of K2O）, with four replicates. The samples were carried out in the months of March （flower blossoming stage）, June （fruits growing stage）, September （grain development） and December （maturation） in all treatments. Foliar analysis carried out in the month of June （fruits growing stage） for the purpose of establishing critical nutrient range values for N, settling down approaches of interpretation of the same one for the Conilon coffee plantations on Cambisoils. The biggest percentages in the yields are obtained with leaves containing N between 2.80% and 3.10%, a value below 2.80% N which they associated with indicative percentages of stable maximum yield that did not surpass the limits of the adequate nutrients supply.
基金Spanish Ministerio de Ciencia e Innovación-EU-FEDER(Project No.BOS2002-02165,CGL2010-21187)the Regional Government of Castilla-León(Project No.SA040/03).
文摘Aims Recent work has identified a worldwide‘economics’spectrum of correlated leaf traits that mainly reflects the compromises between maximizing leaf longevity and short-term productivity.However,during the early stages of tree growth different species tend to exhibit a common strategy,because competition for soil water and nutrients forces the maximization of short-term productivity owing to the need for rapid growth during the most vulnerable part of the tree’s life cycle.Accordingly,our aim here was to compare the variations that occur during ontogeny in the different leaf traits(morphology and leaf chemical composition)of several coexisting Mediterranean woody species differing in their leaf life spans and to test our hypothesis that tree species with a long leaf life span should exhibit larger shifts in leaf characteristics along ontogeny.Methods Six Mediterranean tree species differing in leaf life span,selected from three plots located in central-western Spain,were studied during three growth stages:seedlings,juveniles and mature trees.Leaf life span,leaf morphology(leaf area,dry weight,thickness and mass per unit area)and chemical composition(N and fibre con-centrations)were measured in all six species.The magnitude of the ontogenetic changes in the different traits was estimated and related to the mean leaf longevity of the different species.Important Findings Along ontogeny,strong changes were observed in all variables analysed.The early growth stages showed lower leaf thickness,leaf thickness and mass per unit area and N,cellulose and hemi-cellulose concentrations than mature trees,but a higher lignin content.However,these changes were especially marked in species with a longer leaf life span at maturity.Interspecific dif-ferences in leaf life span,leaf morphology and chemical com-position were stronger at the mature stage than at the seedling stage.We conclude that greater plasticity and more intense strat-egy shifts along ontogeny are necessarily associated with long leaf life span.Our results thus provide a new aspect that should be incorporated into the analysis of the costs and benefits associ-ated with the different strategies related to leaf persistence dis-played by the different species.Accordingly,the intensity of the alterations in leaf traits among different growth stages should be added to the suite of traits that change along the leaf economics spectrum.
基金National Basic Research Program of China(2014CB954500)National Natural Science Foundation of China(31261140364,31370457).
文摘Background:Increasing atmospheric[CO_(2)]can increase photosynthesis and promote plant growth,consequently influencing nitrogen(N)cycling.Yet,there is no systematic information on the N response among different organs of japonica and indica rice genotypes to elevated[CO_(2)]as affected by N application.To investigate the impacts of elevated[CO_(2)]and N fertilization on N uptake and utilization of different genotypic rice(Oryza sativa L.)during grain filling,a free-air CO_(2) enrichment(FACE)experiment with indica cv.Liangyou 084(IIY084)and japonica cv.Wuyunjing 23(WYJ23)was conducted in Eastern China.Crops were exposed to ambient[CO_(2)]and elevated[CO_(2)](200μmol mol^(−1) above ambient)at two levels of N:control(0N)and 22.5 g N m^(−2)(normal N,NN),and they were sampled at 82 days after transplanting(DAT),99 DAT,and maturity,respectively.Results:Under FACE,significant declines of N concentration in all tissues and the whole plants were observed with the greater decrease in leaves and stems at three stages.Positive responses of N use efficiency(NUE)to elevated[CO_(2)]were recorded over the study period.The total N accumulation remained unchanged,while a large amount of N was partitioned to panicles at the expense of leaves and stems.As compared to WYJ23,greater N transportation from roots to aboveground,especially the panicles,was observed on IIY084 accompanied by higher panicle biomass(82 DAT and 99 DAT),N concentrations(maturity),and greater NUE for leaves through the study season.Across all[CO_(2)]and cultivars,N fertilization increased N partitioning to leaves and stems while decreasing that to panicles.Additionally,N supply decreased NUE while stimulating N concentrations and N amounts of rice plants.Among all treatments,IIY084 had the highest N accumulation and allocation in panicles under elevated[CO_(2)]in combination with N fertilizer at maturity.Conclusion:Data from this study were helpful for understanding the temporal N uptake and utilization of different rice genotypes as affected by N availability and suggest that IIY084 promises a considerable prospect for its grain yield and quality under future elevated atmospheric[CO_(2)].
基金This work was supported by grants from the National Key Technologies R&D Program of China(Nos.2006BAD26B0201-1 and 2006BAC01A12)the National Natural Science Foundation of China(grant No.30872011)+1 种基金the National Key Basic Research Program of China(No.2007CB106803)D.Pepper acknowledges grant support from the Australia-China Special Fund for Scientific&Technological Cooperation(CH060165).
文摘The objective of this paper was to assess the congruency of leaf traits and soil characteristics and to analyze the survival strategies of different plant functional types in response to drought and nutrient-poor environ-ments in the southeastern Ke’erqin Sandy Lands in China.Six leaf traits—leaf thickness(TH),density(DN),specific leaf area(SLA),leaf dry weight to fresh weight ratio(DW/FW),leaf N concentration(N mass),and N resorption efficiency(NRE_(mass))-of 42 plant species were investi-gated at four sites.The correlations between leaf traits and soil characteristics-organic C(OC),total N(TN),total P(TP),and soil moisture(SM)-were examined.We found that the six leaf traits across all the 42 species showed large variations and that DW/FW was negatively correlated with OC,TN,TP,and SM(P<0.05),while other leaf traits showed no significant correlations with soil characteristics.To find the dissimilarity to accommodate environment,a hierarchical agglomerative clustering analysis was made of all the species.All the species clustered into three groups except the Scutellaria baicalensis.Species of group III might be most tolerant of an arid environment,and species of group II might avoid nutrient stress in the nutrient-poor environment,while group I was somewhat intermediate.Therefore,species from the different groups may be selected for use in vegetation restoration of different sites based on soil moisture and nutrient conditions.
