不同密度猪毛菜形态结构性状及生物量分配策略的异速关系

植物的生长特性随环境条件的变化具有可塑性,而不同的环境因素对植物可塑性的影响也不尽相同。利用异速分析的方法,通过模拟退化草地恢复过程中猪毛菜（Salsola collina）的不同种群密度（16、44、100、400株/m²）,研究其形态结构性状及生物量分配策略的异速关系在种群密度间的差异。结果表明,种群密度增大能抑制猪毛菜的生长,而且对猪毛菜的株高、根长、一级分枝数、二级分枝数、三级分枝数以及总分枝长均产生了极显著的影响,表明种群密度的变化使得植物的高生长和侧向生长发生了显著变化。种群密度的变化也引起了植物生物量的变化,其中植物根、茎、叶间的生物关系是一种表观可塑性,植物的生长策略未发生改变,只是植物个体大小发生改变引起的生物量分配的变化。植物株高、总分枝长、一级分枝数及繁殖分配的变化,是由种群密度变化引起的,植物的适应策略发生了改变,是真正的可塑性。种群密度改变了植物的繁殖分配策略,而未改变植物叶的分配策略,说明当环境发生变化时,植物调整了其繁殖策略以适应环境因素的改变,以保证种群的生存繁衍。

Allometric relationships between the morphological traits and biomass allocation strategies of Salsola collina under different population density

Plant growth characteristics have plasticity in response to changes of environmental conditions, and different environmental factors have different effects on plant plasticity. The allometric method was used to analyze the morphological-structural traits and biomass allocation strategies by simulating population densities of S. collina (16, 44, 100 and 400 plants/m²) during the restoration of degraded grassland. The results showed that the increased population density could inhibit the growth of S. collina. population density had significant effects on plant height, root length, primary branch number, second-level branch number, third-level branch number, and total branch length, indicating that population density changes have caused significant changes in vertical and lateral growth of S. collina. Population density changes also influenced on the biomass of plant. The biological relationships between roots, stems, and leaves are an "apparent plasticity", and the growth strategy has not changed at all, only the variation of biomass allocation were caused by the change of individual plant size. Changes in plant height, total branch length, primary branch number and reproductive biomass allocation were significantly influenced by population density, representing "true" plasticity. The results showed that variation of population density caused the strategy change of the reproductive allocation rather than the leaf allocation, indicating that when environment changes, plant would adjust the reproductive strategy to adapt to surrounding environmental factors, to ensure the survival and reproduction of the population.