沙丘先锋植物——沙蓬生长可塑性的研究

 无论是大尺度降水的分异还是小尺度土壤湿度的差异都影响植物的生长可塑性。比较科尔沁沙地和腾格里沙漠沙蓬的生长分异, 并用地统计学方法探讨了腾格里沙漠沙蓬生长可塑性的空间变化, 结果表明：科尔沁沙地和腾格里沙漠沙蓬的地上部生物量和地下部生物量都呈线性正相关关系, 地上部生物量和根长都呈对数递增关系；与科尔沁沙地相比, 腾格里沙漠沙蓬的根长增加20％, 根冠比大33.3％, 显然降水分异导致了地区间沙蓬的生长可塑性。地统计学方法进一步分析表明, 腾格里沙漠沙蓬植株因土壤湿度产生的空间异质性是地上部生物量小于根长但大于根重, 说明干旱逆境时沙蓬生长可塑性变化趋势的顺序依次是根长>地上部生物量>地下部生物量, 沙蓬这种生长可塑性特点是其对干旱生境的适应。

Study on Growth Plasticity of Agriophyllum Squarrosum : a Pioneer Species of Plant on Sand Dune

Differentiations of both large-scale precipitation and small-scale soil moisture affect plant plasticity of growth. Comparative experiments on the growth differentiation of Agriophyllum squarrosum in Horqin Sandy Land and Tengger Desert were conducted, and the geostatistical methods were used to investigate the spatial variance of the plant growth plasticity. The results indicated that the aboveground and the underground biomass presented linear positive correlations; the relationships between the aboveground biomass and the length of roots represented logarithmic increases in both sites. Compared with that in Horqin Sandy Land, the root length of A. squarrosum in Tenger Desert was longer by 20 percent, and the root/shoot ratio increased by 33.3 percent. Precipitation difference, obviously, resulted in the differentiation of growth plasticity of A. squarrosum in both areas. A further geostatistical analysis indicated that the spatial heterogeneity of A. squarrosum caused by soil moisture in Tenger Desert was in order of root length>aboveground biomass>root weight. It suggested that the change trend of A. squarrosum growth plasticity was root length>aboveground biomass>underground biomass. The feature of growth plasticity, thus, reflected the adaptation of A. squarrosum plant to drought habitats.