克隆乔木黄牛奶树两种繁殖方式的适合度分析

对黄牛奶树两种生殖方式(克隆生殖和有性生殖)的适合度研究结果表明，不同生境下,黄牛奶树繁殖及占据空间的方式有一定差异.在水肥资源丰富、郁闭度较大(常绿阔叶林和竹林)条件下，克隆生殖和有性生殖幼苗存活率均较高，占据空间的能力较强，但克隆苗在数量和占据空间的能力上占较大优势，主要以克隆方式进行繁殖；水肥资源贫乏、光照较强的条件下，两类苗存活率和占据空间能力均较低，实生苗在数量和占据空间能力上占优势.黄牛奶树两种繁殖方式的瓶颈期不同，有性生殖的瓶颈期在种子到幼苗阶段，而克隆苗在幼苗到成株阶段.黄牛奶树的入侵过程是先以实生苗侵入一个地点定居，在郁闭度较大、水肥良好的条件下，以克隆方式迅速占领空间.生长初期克隆苗表现出极大的优势，后期(15龄以上)则优势不复存在.

Fitness analysis of seed-and vegetative reproduction of clonal tree Symplocos laurina

There are two ways in Symplocos laurina propagation,clonal and sexual reproduction.The study showed that under different habitat conditions,Symplocos laurina could adopt different ways to propagate and occupy space.In conditions with abundant water and nutrient resources,such as in evergreen broad-leaved forests or bamboo forests,the survival rate and space-occupying ability of both ramets and sexual seedlings were relatively high,with clonal ramets took advantage in terms of number and space,suggesting that clonal propagation was the dominant way in such environments.Oppositely,in habitats lack of sufficient nutrition,the survival rate and space-occupying ability of seedlings were low,and grown-up plantlets would preempt in number and space occupation.Bottleneck in sexual propagation appeared in the stage from seed to seedling,while clonal propagation appeared during the period from seedling to ramet.The way of Symplocos laurina invasion was to settle a plantlet,and then occupied the space rapidly by clonal growth,with clonal seedlings dominated in initial stage and lost the advantage after 15 ages.