外方山草本植物叶片生长期C、N、P生态化学计量学特征的变化

为揭示同一生活型草本植物生长期内C、N、P生态化学计量学特征,在豫西南外方山设置羊胡子草(Carex rigescens)、芒草(Miscanthus sinensis)、野菊花(Dendranthema indicum)样地,测定生长期内叶片C、N、P含量及其生态化学计量比。结果表明:同一生活型种间植物叶片化学计量学特征具有多变性,胡子草、芒草、野菊花等3种植物生长期内叶片C含量平均为447.6 g/kg、448.1 g/kg和459.9 g/kg,N含量为26.8 g/kg、23.5 g/kg和25.6 g/kg,P含量为1.9 g/kg、1.5 g/kg和2.0 g/kg;3种植物综合变异系数排序为P含量(45.0%)C/P值(33.2%)N/P值(30.1%)C/N值(26.0%)N含量(25.3%)C含量(2.0%),C含量最稳定,N含量次之,P含量较不稳定;C含量与N、P含量负相关性均不显著(P0.05),P含量与N含量正相关性极显著(r=0.736,P0.01),N含量与C/N值负相关性极显著(r=-0.700,P0.01),P含量与C/P值负相关性极显著(r=-0.891,P0.01),C/N值与C/P值正相关性显著(r=0.283,P0.05);植物种类对叶片C含量影响显著(P0.05),N含量、P含量、C/N值与C/P值主要受生长期采样时间的影响(P0.05),物种种类与采样时间对N/P值影响不显著(P0.05)。研究区域植物叶片生态化学计量特征时,应考虑植物种类与生长期的影响。

Variations of Herbaceous Plant Leaf C,N, P Ecological Stoichiometrical Characteristics during Growth Period in Waifang Mountain

In order to explore variations of leaf ecological stoichiometrical characteristics during the growth period of herbaceous plants with the same life form,three kinds of experimental plots with Carex rigescens,Miscanthus sinensis and Dendranthema indicum were chosen in Waifang mountain area in Southwest of Henan province,China.We monitored carbon,nitrogen and phosphorus contents,C/N,C/P and N/P mass ratios in three plant species mentioned above at different growth dates from May to October,2014.The results showed that plant leaf carbon,nitrogen and phosphorus contents and C/N/P stoichiometrical characteristics had variability among plant species.The average content in leaves of three species were 447.6 g/kg,448.1 g/kg and 459.9 g/kg for carbon,26.8 g/kg,23.5 g/kg and 25.6 g/kg for nitrogen,and 1.9 g/kg,1.5 g/kg and 2.0 g/kg for phosphorus during the growth period,respectively.Considering the comprehensive analysis based on total variation(resulting from two factors:sampling date and species),the rank of coefficient of variation (CV) for each parameter was phosphorus content(45.0％) ＞C/P ratio(33.2％) ＞ N/P ratio (30.1％) ＞ C/N ratio (26.0％) ＞ nitrogen content (25.3％) ＞ carbon content (2.0％),carbon content had a minimum variation width,followed by nitrogen element,phosphorus element was less stable.The negative correlation between carbon content and nitrogen content was not significant(P ＞ 0.05),and the correlation between carbon content and phosphorus content was the same.But phosphorus content and nitrogen content were significantly positively correlated (r =0.736,P ＜0.01).Nitrogen content and C/N ratio were significantly negatively correlated(r =-0.700,P ＜ 0.01),phosphorus content and C/P ratio were significantly negatively correlated(r =-0.891,P ＜ 0.01),C/N ratio and C/P ratio were significantly positively correlated (r =0.283,P ＜ 0.05).The effect of plant species on leaf carbon content was significant (P ＜ 0.05),the nitrogen content,phosphorus content,C/N ratio and C/P ratio were mainly affected by sampling date (P ＜ 0.05),the N/P ratio was not affected by sampling time and plant species (P ＞ 0.05).When plant leaf ecological stoichiometrical characteristics was studied in some regional ecosystems,the effects of plant species and growth period should be considered.