云南喀斯特断陷盆地典型群落植物生态化学计量学特征

Characteristics of leaf ecological stoichiometry in typical plant communities in karst fault-depression basins of Yunnan Province

喀斯特地区地质化学、气候和人类活动强烈影响植物群落组成、植物元素含量和化学计量特征。本文以云南省蒙自市断陷盆地区天然林、灌丛和草地群落植物为对象,研究了植物叶片12种元素含量和生态化学计量特征。结果显示:研究区内植物元素含量存在较大差异,各元素含量从高到低的顺序依次是C>Ca>N>K>Mg>P>Fe>Al>Zn>Mn>Na>Cu,三种群落植物N、K、Ca、Mg、Al、Cu、Zn、Mn含量存在显著差异。天然林与灌丛群落植物生长受到P含量的限制,而草地群落植物生长受到N与P单独或共同的影响。草地群落植物C∶N、C∶Ca、C∶Mg显著高于天然林与灌丛植物,N∶P则呈现相反格局。三种群落间植物C∶Ca比例显著不同,表现为草地>天然林>灌丛。在研究区内,有27对元素含量呈现显著相关,占总元素对的40.9%。这些结果表明,云南喀斯特断陷盆地植物为适应环境,形成了独特的化学计量特征和适应策略。

Plant community composition,elemental content of plants and stoicheometric characteristics are strongly influenced by geological chemistry,climate and human activities in karst areas.This study is concerned with plants sampled in the natural forest,shrub and grassland communities in a karst fault-depression basin,Mengzi,Yunnan.The purpose is to clarify the content of 12 elements and stoichiometric ratios in leaves of this area.The results show that el⁃emental concentrations of leaves are of an order C>Ca>N>K>Mg>P>Fe>Al>Zn>Mn>Na>Cu,with signifi⁃cant differences in N,K,Ca,Mg,Al,Cu,Zn and Mn concentrations for plants among three communities.P content lim⁃its growth of plants in natural forest and shrub communities,and N and P contents separately or jointly affect growth of plants in grassland communities.In grassland communities,ratios C∶N,C∶Ca and C∶Mg of plants are significantly higher,while N∶P ratio lower than those in the natural forest and shrub communities.The C∶Ca ratio of plants signif⁃icantly differs among the three communities,with the order of grasslands>natural forests>shrubs.In statistics,27 pairs of elements(40.9%of total element pairs)display significant correlations.The results suggest that plants have formed unique ecological stoichiometric traits to adapt for local environmental conditions in karst fault-depression ba⁃sins of Yunnan.