不同邻体大头茶幼苗的适应特征

CHARACTERISTICS OF ADAPTATION OF GORDONIA ACUMINATA SEEDLINGS TO DIFFERENT NEIGHBORS

在亚热带常绿阔叶林自然林窗下，以大头茶幼苗为基株，分别以马尾松、川灰木和大头茶幼苗为邻体。研究不同邻体如何改变可利用资源，影响大头茶幼苗基株生长动态和形态、树冠结构和生物量效应，并探讨影响基株生长的邻体的主导因素。结果表明，不同邻体的生长和截光效应差异明显；基株生长特征与邻体的树高、叶生物量、总生物量和树冠距地表１０ｃｍ处截光量相关极小，却与邻体树冠距地表３０ｃｍ处截光量相关极大，故影响基株生长的邻体主导因素是遮挡基株树冠的邻体的可利用光资源；基株生长动态，如树高、叶数、叶面积和叶大小，树冠结构和生物量显著受到不同邻体的影响，并且基株树高及增长量、叶面积、冠幅和生物量均为大头茶单株（ＧＮＯ）＞大头茶＋川灰木（ＧＮＳ）＞大头茶＋马尾松（ＧＮＰ）＞大头茶＋大头茶（ＧＮＧ）。大头茶幼苗种内竞争明显强于种间竞争。

The present study is to investigate influnces on resource availability for “target”Gordonia acuminata seedlings,their growth,morphology、canopy structure and biomass by their different neighbors individuals of Pinus massoniana,Symplocos setchuenensis and Gordonia acuminata seedlings .Attempts,was also made to find out the main factors of the neighbor influence on the growth of the “target” individuals in natural gap of subtropical evergreen broadleaved forest.The results show that the growth and light interception differed significantly among different neighbors:The growth characters of target individuals were poorly correlated with the height、the leaf biomass、total biomass of neighbors and their light interception at 10 cm height above ground in canopy,but were highly correlated with their light interception at 30 cm height above ground.Therefore,the major factor for growth of the target individuals was light availability of the neighbor shading the target individuals.The growth dynamics of target individuals,in terms of tree height,number of leaves,leaf area,leaf size,canopy structure and biomass,were significantly influenced by different neighbors.The height and growth、the leaf area、the canopy width and the biomass of the target individuals were larger in G.acuminata+no neighbor than those in G.acuminata+S.setchuenensis those of which were in turn larger than those in G.acuminata+P.massoniana.In G. acuminata+G.acuminata,those characters were smallest.The intraspecific competition in G.acuminata was greater than the interspecific one.