珍稀濒危植物紫纹兜兰的种群结构和数量动态

Population Structure and Quantitative Dynamics of Rare and Endangered Plant Paphiopedilum purpuratum

通过对广东省河源市紫金县白溪省级自然保护区紫纹兜兰(Paphiopedilum purpuratum)进行样方调查,运用种群生命表、存活曲线、种群生存函数值和时间序列预测分析方法,研究紫纹兜兰种群的动态变化过程,揭示各龄级植株的数量动态和变化规律。结果表明,紫纹兜兰龄级以幼龄为主,幼龄阶段占整个种群的54.73%,年龄结构为稳定型。种群年龄结构的动态指数Vpi为0.33、Vpi’为0.07,均大于0,紫纹兜兰的存活曲线更接近Deevey-Ⅱ型,表明该种群目前属于稳定型种群。累计死亡率函数和危险率函数上升,生存率函数下降,死亡密度函数波动较大。从时间序列预测分析表明,种群具备一定的恢复能力,但是种群整体数量随时间的增加,成年植株逐渐增加,幼苗减少。平均开花和结实率仅为16.94%和3.29%,种子没有胚乳而营养不足,在自然环境下很难发育成幼苗,主要靠分蘖植株繁殖,因此对紫纹兜兰幼苗的保护很关键。

Sample quadrat survey was conducted on Paphiopedilum purpuratum in Baixi Provincial Nature Reserve of Zijin County,Heyuan City,Guangdong Province.The dynamic changes of the planting stages of population of P.purpuratum were studied by using population life table,survival curve table,survival function value and time series prediction analysis method.Quantitative dynamics and variation of plants.The results showed that seedling was the dominant species,approximately 54.73%of the population,and the age structure was stable.The dynamic index Vpi of population age structure was 0.33,Vpi’was 0.07.Both dynamic indices were more than 0,the survival curve type is closer to Deevey-Ⅱ,indicating that the population was stable at present.Both of them while the cumulative mortality and risk function increase,survival function decreases,and death density function fluctuates greatly.The time sequence prediction analysis shows that P.purpuratum has a certain recovery ability,but the overall population increased with time,the adult plants gradually increased,and the seedlings decreased.The average flowering and seed setting rate of P.purpuratum is only 16.94%and 3.29%.The seed has no endosperm and under nutrition,which makes it difficult to develop into a seedling in the nature,and propagation mainly by tillers,so it was very important for the protection of P.purpuratum seedlings.