木本克隆植物中国沙棘种群数量与结构对土壤水分的响应

Population quantity and population structure in response to soil moisture in the clonal tree species Hippophae rhamniodes L.subsp sinensis

木本克隆植物中国沙棘能够通过克隆生长调节来适应土壤水分有效性或土壤水分异质性,这种调节最终影响其种群数量和结构特征。为了验证这一假设,根据野外调查数据分析了中国沙棘种群数量和结构等对土壤水分有效性的可塑性响应。结果表明,随着土壤水分有效性的提高,中国沙棘克隆种群生物量及个体生长量增大,种群发育进程和个体大小分化加速,而克隆子株密度以及种群增长率呈现先增加后减小的趋势;增长型年龄结构的种群可形成合理的等级结构,其不同高度级的个体数量分布符合直线模型。据此,木本植物克隆可塑性变化最终必然导致种群数和结构改变的假设得以验证。

Clonal tree species Hippophae rhamniodes L. subsp sinensis can adapt themselves to the supplying availability or heterogeneity of environmental resources by clonal growth regulation,and the regulation finally affects the characteristics of population quantity and its structure. Based on the investigation of clonal growth under different soil moisture conditions,ramets density,population biomass and population structure are analyzed for testing the hypothesis mentioned above. The results show that the population biomass and its growth increment increase obviously with the rising of the level of soil moisture supply,and the rising of level of soil moisture supply also promotes the population development and individual size polariza, tion. The ramets density,and the increasing rate of clone population, however,tend to increase first and then decrease. Besides ,the results indicate that the population with increasing age structure can form a rational height class structure observing a linear mode between height classes and its number of ramets. Therefore,the hyothesis can be confirmed that the plastic change of the clonal tree species will definitely lead to the change of the population number and its structure.