松嫩草原水淹恢复演替群落五脉山黧豆无性系生长及根茎构件年龄结构

Clonal growth and age structure of module on rhizome of Lathyrus quinquenervius population in the communities of restoration succession of the flooded meadow in the Songnen Plains of China

五脉山黧豆是长根茎型豆科牧草,是典型的无性系植物。在松嫩平原生长季后期,五脉山黧豆无性系种群生物量59.6%分配于分株,40.4%分配于根茎。经过对样本的观察,创建了按实际生活年限划分豆科植物根茎年龄的方法。五脉山黧豆的根茎最多可生活3个年度,但至生长季后期3龄级根茎存活量甚少,并已经失去了繁殖力。当年形成的1龄级根茎大多是从2龄级根茎上产生。2龄级根茎几乎没有死亡。根茎长度的年龄结构表现为1龄级与2龄级大体相同,3龄级陡度减少。根茎生物量的1龄级比率比根茎长度的有所增加,2龄和3龄级则有不同程度的减少。五脉山黧豆无性系种群采用了优先向1龄级根茎输送与贮藏营养物质的生存与发展策略。在水淹后恢复演替群落具有地被植物种间竞争的条件下,五脉山黧豆仍可以通过指数函数迅速地增加着无性系的子代数量,同时也迅速地扩展着无性系的生态位空间。

Lathyrus quinquenervius is a typical clonal leguminous plant with long rhizome. In the late period of growing season in the Songnen Plains of China, L. quinquenervius clonal population allotted 59.6% of biomass to the ramets and 40.4% to the rhizomes. By observing to the samples, a method that according to actual (lifespan) could divide age classes to the rhizomes of leguminous plant was established. The rhizomes of L. quinquenervius could live for 3 years at most, but the 3rd age class rhizomes were very little and lost clonal reproductive capacity until the late period of growing season. Most 1st age class rhizomes of present year developed from the 2nd age classes. The 2nd age class rhizomes almost didn't die. The age structure of rhizome length showed that the 1st and the 2nd age classes were equal on the whole, the 3rd age suddenly reduced. The percentage of the 1st age classes rhizome biomass were more than that of rhizome length, the 2nd and the 3rd age classes differently decreased. L. quinquenervius clonal population adopted the survival and development strategies to preferentially transport and store nutrition matter to the 1st age class rhizomes. Under the communities with ground surface vegetation interspecies competition during restoration succession of the flooded meadow, the offspring number of existed clones still increased exponentially, and the niche space expanded rapidly at the same time.