米氏冰草营养繁殖潜在种群与现实种群的关系

为了解米氏冰草种群在沙地的适应机制,本研究采取种群繁殖生态学的方法,对米氏冰草种群在沙地植被恢复的不同阶段,营养繁殖潜在种群与现实种群的关系进行了研究。结果表明,在米氏冰草营养繁殖潜在种群中,冬性苗的比率比冬性芽高3～4倍;营养繁殖现实种群中99% 以上是由前一年的冬性苗转化形成的。冬性苗中的分蘖节苗转化为现实种群的比率略高于根茎苗。不同生境之间,固定沙地的米氏冰草的冬性根茎苗和冬性分蘖节苗的转化效率分别比流动沙地高1.6～1.8倍。反映了随着沙地植被的恢复,米氏冰草营养繁殖潜在种群对现实种群的作用逐渐增强,从而揭示了无性系植物在沙地的繁殖扩散及调节适应机理,为种群繁殖生态学的研究提供理论依据。

Relationship between vegetative potential populations and actual populations of Agropyron michnoi

To understand the adaptive mechanisms in sandy land, the relationship between potential populations and actual populations of vegetative reproduction of Agropyron michnoi modules was studied in different growth areas on sandy land. For vegetative potential populations, the percentage of the juvenile seedlings was 3-4 times higher than that of the dormancy buds and 99% of the vegetative actual population was formed from juvenile seedlings of the previous year. The conversion ratio to juvenile seedlings was greater from the tillering nod seedlings than from the rhizome seedlings. The conversion ratio of winter rhizome seedlings and winter tillering nod seedlings on fixed sandy land was 1.6-1.8 times greater than that on shifting sandy land. These results suggest that as desertified grassland recovers, the effect of vegetative potential populations of A. michnoi on real populations gradually increases thus revealing the mechanisms of reproductive extention and adaptability, and enriching and extending the theories of population reproductive ecology.