浙江大盘山濒危植物七子花的种群结构

Population Structure of Heptacodium miconioides , an Endangered Species, in Dapan Mountain of Zhejiang Province

七子花是我国特有的单种属植物,也是受重点保护的濒危植物.以浙江大盘山七子花为对象,从基株和无性系分株2个层次上进行种群结构研究.结果表明,各样地基株和分株种群中,均缺少Ⅰ级幼苗;基株种群中Ⅲ、Ⅳ径级个体所占比例最大,但在多数局部地段,由于数量少,呈现衰退.分株种群中Ⅱ、Ⅲ龄级个体所占比例最大.总体来看,这里的七子花种群相对稳定,但在局部地段,七子花数量较少,面临局部消失的风险.中等海拔处每基株含有的分株数较少,海拔较低及较高处相对较多.径级Ⅴ的个体平均具有较多的分株数,显著高于径级Ⅲ的分株数,与径级Ⅳ的差异处于临界显著,而与径级Ⅱ的差异不显著.大盘山种群主要靠无性繁殖更新.研究表明,如果生境没有大的变化,这里的七子花基本上能够维持下来.大盘山可能是七子花最大种群分布点,因此,在这里应该建立一个保护区.

Heptacodium miconioides Rehd. (Caprifoliaceae), seven-son-flower, is an endangered species endemic to China. The population structure of H. miconioides was analyzed at genet and ramet levels, respectively, in Dapan Mountain of Zhejiang Province. No individual of size class Ⅰ (height<0. 33 m) was found in all studied sites. Size-class Ⅲ and Ⅳ had most abundant individuals. At ramet level, size-class Ⅱ and M had most abundant stems. Generally, size-class structure indicated a relatively stable situation in Da-pan Mountain. However, in some sites, H. miconioides had the risk of local extinction. Sites at mid-altitude had lowest stems per individual, whereas more stems per individual were found at lower or higher sites. Individuals of the largest size class (size class Ⅴ) had significant more stems per individual than size class Ⅲ and critically significant more than size class Ⅳ. Our observation indicated that the population of Dapan Mountain was regenerated via asexual reproduction. These results showed that H. miconioides in Dapan Mountain could be maintained if no dramatic changes in the habitats. A reserve should be set because Dapan Mountain may be the largest population of H. miconioides.