伊犁河谷地天然假苇拂子茅种群冬眠构件的结构

为探讨伊犁河谷地内分布的天然假苇拂子茅(Calamagrostis pseudophragmites)无性系种群的冬眠构件结构,分析冬眠构件对其种群大小、动态以及种群维持和更新的影响,按无性系植物的构件理论及根茎型无性系禾草种群年龄结构的研究方法,通过生长季末期单位面积取样,分析了新疆伊犁河谷地3个不同生境中假苇拂子茅的冬眠构件结构以及潜在种群与现实种群的数量特征。结果表明:在伊犁河谷地,假苇拂子茅无性系的冬眠构件是由冬眠芽和冬眠苗组成;在生长季末期,3个生境的冬性苗种群均属于趋于稳定型的年龄结构,且苗库最高由5个龄级组成,冬眠苗与冬眠芽总数在不同生境间差异显著;3个生境的分蘖节芽种群均属于增长型的年龄结构,最高达5个龄级。在假苇拂子茅的冬眠构件中,由根茎顶芽和分蘖节芽构成了本地区具有实际生态意义的潜在种群,其中又以分蘖节芽种群对翌年种群更新速率的影响最大,从而保障了其在不同生境上的适应性和相对稳定性,也是实现其在伊犁河谷地区持续繁荣的关键所在。

Dormancy Module Structures of Calamagrostis pseudophragmites Populations in the Yily River Valley Area of Xinjiang,China

Vegetative propagation has an important position and function in both life history and changes of Calamagrostis pseudophragmites populations. Thus, it is very important to investigate dormancy module structures and analyze the effect of dormancy structure on the size, dynamics, maintaining and regeneration of clonal populations. Relationships between dormancy modules (potential populations) and tillers (realistic populations), and population dynamics with different habitats were studied in the Yily River Valley area of Xinjiang, China. Results showed that, the dormancy modules of C. pseudophragmites clone in the Ily River Valley area consisted of RAB (rhizome apical bud), TBV (tillering node buds of vegetative ramets), TBR (tillering node buds of reproductive ramets) and dormancy seedlings. By the end of C. pseudophragmites clone growing season, dormancy seedlings showed a stable age structure and consisted of five age classes. There were significant differences between total buds and total dormancy seedlings under different habitats. The tillering node buds had the most potential impact on the realistic population, and then dormancy seedlings and RAB successively affect the actual population. Among all the dormancy modules, the potential population with actual ecological meanings was constructed by tillering node buds and rhizome apical buds, and the former had the most effect on regeneration rate of the next year. Those characters of dormancy modules provided both adaptability and relative stability of C. pseudophragmites population at different habitats. Meanwhile, those characters were also the key factors which sustained the prosperity of C. pseudophragmites population in the Yily River Valley area of Xinjiang.