不同坡位水青树种群生殖特征的差异分析

Different Reproductive Characteristics of Tetracentron sinense Populations at Different Slope Positions

通过对濒危植物水青树Tetracentron sinense构件和个体水平上的生殖分配、种子萌发与幼苗初期生长特性的观测,分析不同坡位水青树种群生殖特征的差异,探讨水青树种群对生境的适应对策。本研究对来自于四川省美姑大风顶国家级自然保护区中坡位和低坡位的两个水青树天然种群的生殖分配(Reproductive Allocation,RA)、生殖投入、营养投入及种子萌发特性进行测算,采用多重比较、单因素方差分析等多种方法分析两个种群的生殖特征差异。结果表明:(1)在花期,下坡位种群构件和个体水平的RA均极显著大于中坡位种群;在果期两者差异不显著;(2)在花期和果期,水青树生殖枝的生殖投入与营养投入均呈极显著正相关,RA与营养投入呈显著或极显著负相关;(3)下坡位水青树种群的种子萌发率和幼苗生长动态均明显优于中坡位种群。由此可知,坡位不同,水青树所处的生境条件也不同,从而导致了两个水青树种群生殖特征的差异,这可能是水青树在长期演化过程中形成的生殖适应性机制。

Different reproductive characteristics of endangered plant Tetracentron sinense populations at different slope positions is analyzed and the adaptive strategy of T.sinense to habitat is discussed through the investigation of its reproductive allocation at the component and individual level,seed germination and seedling growth characteristics.RA(reproductive allocation),reproductive input,vegetative input and seed germination characteristics of two populations of T.sinense at the mesoslope and on the downhill in Meigu Dafengding National Nature Reserve are measured,and differences of reproductive characteristics between the two populations are analyzed by multi-comparison,one-way variance analysis and other methods.The results are as follows:(1)In the flowering period,RA of the population on the downhill is significantly higher than that on the mesoslope at both the component and individual level while the difference between the two is not significant in fruiting period.(2)In the flowering and fruiting periods,the reproductive input of T.sinense branches is significantly positively correlated to the vegetative input while RA has a significant or extremely significant negative correlation with the vegetative input.(3)The seed germination rate and seedling growth of T.sinense on the downhill are significantly better than that on the mesoslope.It indicates that the difference of reproductive characteristics is resulted by the different habitat at different slope positions,which is possibly a reproductive adaptation mechanism formed in the long-term evolution of T.sinense.