民勤荒漠区主要灌木叶片C、N、P化学计量特征的季节变化

为探究不同灌木叶片C、N、P化学计量特征季节变化规律,揭示荒漠植物对环境的适应策略,以民勤荒漠区4种主要灌木梭梭、沙拐枣、唐古特白刺、柠条锦鸡儿为研究对象,分析不同荒漠植物在生长季内叶片的C、N、P含量及其计量比变化特征。结果表明:(1)沙拐枣、柠条锦鸡儿叶片C含量显著高于唐古特白刺、梭梭(P<0.05),且唐古特白刺显著高于梭梭,沙拐枣与柠条锦鸡儿差异不显著;唐古特白刺叶片N含量显著高于其他3种植物叶片;唐古特白刺叶片P含量最高,并显著高于柠条锦鸡儿,但两者均与梭梭和沙拐枣差异不显著。(2)4种荒漠植物叶片C、N、P含量及其计量比各指标在生长季节内的变异系数表现为:P(28.34%)>C∶P(24.70%)>N∶P(19.07%)>N(17.49%)>C∶N(16.89%)>C(2.91%)。(3)C含量与N、P含量呈不显著正相关关系;除沙拐枣,其他叶片N含量与P含量呈显著正相关关系,4种荒漠植物叶片N∶P值的变化主要由P含量变化决定。(4)植物叶片C、N、C∶N、C∶P和N∶P含量的变异主要受植物种类影响,植物叶片P含量的变异主要受生长季节影响。研究发现,民勤荒漠4种灌木植物叶片C、N、P含量及C∶N、C∶P和N∶P在生长季内因物种而不同,它们在生长季内变异系数在植物种之间也存在差异。

Seasonal Variations of C,N and P Stoichiometry Characteristics in Leaves of Main Shrubs in Minqin Arid Desert Area

To explore the seasonal variation rule of C,N and P stoichiometric characteristics of different shrub plant leaves,and reveal the adaptation strategies of desert plants to environment,with four main shrub plants in Minqin arid desert area(Haloxylon ammodendron,Calligonum arborescens,Nitraria tangutorum,Caragana korshinskii Kom.)as the research object,and in the growing season,we analyzed C,N and P contents and their measurement ratios.The results showed that:(1)The content of C in the leaves of C.arborescens and C.korshinskii Kom.were significantly higher than that of N.tangutorum and H.ammodendron(P<0.05);N.tangutorum were significantly higher than H.ammodendron(P<0.05);the difference between C.arborescens and C.korshinskii Kom.was not significant.The N content in the leaves of N.tangutorum was significantly higher than that of the other three plants(P<0.05);the P content of N.tangutorum was the highest,and was significantly higher than that of C.korshinskii Kom.,but both of them were not significantly different from H.ammodendron and Calligonum mongolicum.(2)Based on the total variation(resulting from two factors:season and species)for each parameter in these four shrubs,the rank of CV for each parameter was P(28.34%)>C∶P(24.70%)>N∶P(19.07%)>N(17.49%)>C∶N(16.89%)>C(2.91%).(3)C content was positively correlated with N and P contents but not significantly(P>0.05);except for C.mongolicum,the N content in leaves was significantly positively correlated with the P content(P<0.05),the N∶P of four desert plants in Minqin was mainly determined by the change of P content.(4)Leaf C and N contents and leaf C∶N,C∶P and N∶P mass ratios were mainly determined by plant species,and leaf P content was mainly affected by growing season.It was thus clear that the contents of C,N,P and C∶N,C∶P and N∶P ratios in the leaves of desert plants in Minqin varied from species to species in the growing season,and their coefficient of variation in the growing season were also different among plant species.