摘要
羊柴(Hedysarum laeve)是豆科多年生半灌木,在自然条件下可以同时进行有性繁殖和克隆繁殖。该文在野外条件下研究了不同水平的水分和养分处理对羊柴种群的繁殖权衡的影响。结果表明,与对照相比,增加一定量的水分处理显著减少了花和荚果的生物量;显著增加了克隆分株枝的生物量,显著减少了分株根茎的生物量,但没有影响其它部分的生物量。增加一定量的水分会抑制有性繁殖,改变生物量对克隆繁殖分株各部分的分配比例。与对照相比,增加一定量的养分能够促进有性繁殖,抑制克隆繁殖。
Aims Hedysarum laeve is a rhizomatous perennial semi-shrub, which reproduces both sexually and clonally in natural populations. Study of reproduction trade-off of this species could provide theoretical foundation for the management of natural grassland. The specific goal of this study was to determine if there is a trade-off between sexual and clonal reproduction in H. laeve natural population in response to water and nutrient supplies.
Methods During the growing season of June to September 2005, we conducted two field experiments in Mu-Us Sandland using 1 m×1 m plots. Different amounts of water were added to the plots to imitate 0, 16, 32 and 64 mm of precipitation. Nutrient additions were 0, 30, 60, 90 and 120 g. The biomass of H. laeve ramets in each plot was measured in late September 2005.
Important findings Increasing water supply decreased both biomass and biomass allocation to flowers, fruit sets and rhizomes, whereas it increased biomass and biomass allocation to clonal ramet shoots. Within increasing water supply, biomass allocation to sexual reproduction decreased, whereas biomass allocation to clonal reproduction did not change. However, increasing water supply increased biomass allocation to ramet shoots but decreased that to ramet rhizomes. Therefore, increase in water supply inhibited sexual reproduction and thus changed the biomass allocation to clonal reproduction. Increasing nutrient supply increased fruit biomass and decreased biomass of shoots, leaves and rhizomes of clonal ramets, but did not affect biomass of other parts. With increasing nutrient supply, biomass allocation to fruits increased, whereas biomass allocation to leaves and shoots of clonal ramets decreased. Therefore, increase in nutrient supply enhanced sexual reproduction, but reduced clonal reproduction. We conclude that there is a trade-off between the sexual and clonal reproduction in H. laeve population in responses to water and nutrient supplies. The plastic responses of sexual and clonal reproduction of H. laeve popul
出处
《植物生态学报》
CAS
CSCD
北大核心
2007年第4期658-664,共7页
Chinese Journal of Plant Ecology
基金
国家自然科学基金项目(30330130
30570281)
国家科技部973项目(2007CB106802)
科技部国家自然科技资源共享平台建设项目(2005DKA21006)
关键词
羊柴
有性繁殖
克隆繁殖
养分
水分
生物量分配
Hedysarum laeve, sexual reproduction, clonal reproduction, nutrient, water, biomass allocation
