内蒙古锡林郭勒高原大针茅种群分株构件数量性状的地理变异研究

采用单因素方差分析、变异组分分析和分形几何学的原理和方法，对内蒙古锡林郭勒盟不同气候条件下的三个大针茅种群分株构件数量性状进行了研究，并结合它们所在生境特点对所得结果进行了分析。结果显示：（1）整个生长季内，不同种群大针茅营养枝高度的生长模式不同；营养枝高度和生殖枝高度在种群间差异显著，且多数变异存在于种群之间；（2）在不同生长期内，大针茅种群地上部干重与植株高度之间存在显著的分形关系；在无强度干扰的情况下，大针茅种群营养枝分形维数的大小与大针茅营养枝地上部干重的累积程度是一致的；但在长期严重干旱条件下，分形维数值表现为快速增加；（3）整个生长季内，同一生境条件下大针茅种群营养枝地上部干重与植株高度之间也存在显著的分形关系，且不同样地间分形维数值差异显著。不同生境条件下大针茅种群分株构件数量性状的差异是对所在生境长期适应、自然选择的结果。

Geographic Variations of Stipa grandis Clonal Populations in the Xilingol Plateau of Inner Mongolia

The quantitative characters of Stipa grandis clonal populations found in three habitats with different climatic conditions in the Xilingol plateau of Inner Mongolia, were studied by means of one way ANOVA, analysis of variance components and fractal geometry. (1) The three populations had different growth patterns in plant height of vegetative modules in the growing season; plant height of vegetative modules or reproductive modules varied significantly among S. grandis populations and most variation existed among populations. (2) There were significant fractal relationships between aboveground dry matter weight and height of vegetative modules of S. grandis populations in different growth periods of the plant; the fractal dimension value was consistent with the biomass accumulation of vegetative modules when the habitats were not intensively disturbed; while a very rapid increase happened under long-term severe drought conditions. (3) There were also significant fractal relationships between aboveground dry matter weight and plant height of vegetative modules of S. grandis populations in the growing season, furthermore, the values of fractal dimension varied significantly among different populations. All the divergences among different habitats were supposed to be attributed to long-term local adaptation and natural selection.