毛乌素沙地油蒿与杨柴异速生长模式及个体大小的种内竞争调节

通过对油蒿与杨柴种群在不同密度下个体大小与异速生长变化模式的比较研究,初步得出以下结论:①油蒿种群的个体平均大小、高径比平均值及静态异速生长指数均未随着密度的增加而发生明显的变化,其静态异速生长曲线都符合"简单的"异速生长类型。②杨柴种群的个体平均大小随着密度的增加则不断减小,且其自疏指数小于-3/2,这主要是由于种群在高密度时冠层未达到密接的缘故,而且可以将种群内个体的总植冠投影面积和是否达到最大值作为判断冠层密接的标准。③杨柴种群的高径比平均值及静态异速生长指数随着密度的增加也未发生明显变化,其静态异速生长曲线也符合"简单的"异速生长类型,表明杨柴的异速生长特性并未随着光竞争强度的增加而发生变化,这可能是因为杨柴能通过根状茎繁殖产生新枝来寻找更合适的生境从而避免了光竞争。

Adjustment of Artemisia ordosica and Hedysarum laeve's Allometric Pattern and Individual's Size to the Intra-species Competition in Mu Us Sandland

Through the study of the change in individual's size and allometric pattern of Artemisia ordosica and Hedysarum laeve populations distributing on the Mu Us Sandland,this paper has gained the following conclusions primarily:(1) The Artemisia ordosica individual's average size,average Height/Diameter ratio and static allometric coefficient don't change with the increase of density,and the curve of the static allometry is fit with the simple allometry type,this is because that the settlement and the growth pattern of Artemisia ordosica individual are mainly influenced by the water condition of the micro-habitat.(2) The average size of Hedysarum laeve individual decreases with density,and its self-thinning power is less than 3/2,this is probably because the canopy hasn't reach the 100% cover in higher density,and we can judge the 100% cover of the canopy by seeing if the total area of individual's canopy projection reach the ceiling value.(3) Hedysarum laeve individual's average size,average Height/Diameter ratio,and static allometric coefficient don't change with the increase of density,and the curve of the static allometry is fit with the simple allometry type too,that means the Hedysarum laeve's character of allometry don't change with the increase of light competition's intensity,this is probably because it can find a more suitable habitat by its rhizome's reproduction to produce a new branch,so it can avoid the light competition.