红毛草Rhynchelytrum repens(Willd.)C.E.Hubbard的繁殖特性

The Reproductive Properties of Rhynchelytrum repens(Willd.)C. E. Hubbard

从繁殖生态学的角度对红毛草Rhynchelytrum repens(Willd.)C.E.Hubbard的繁殖特性进行了研究。采用盆栽试验与发芽试验,分别研究了4种不同种植密度下红毛草的资源分配情况和4年内红毛草的种子寿命与萌发情况。结果显示:①盆栽试验中,低密度种植红毛草的单株总生物量、茎叶生物量、根生物量与根冠比高于高密度种植差异达显著水平(p<0.05);花的生物量在相对低密度下低于高密度的量,差异显著(p<0.05);②高密度种植红毛草的RE(Reproductive effort)值大于低密度种植的RE值,而且差异显著(p<0.05),显示红毛草在生长胁迫下分配更多的资源到繁殖器官中;③发芽试验中,红毛草种子在高温胁迫下(45℃)发芽率显著下降(p<0.05),但仍维持在一定的水平(30.2%),显示了红毛草对高温的适应能力;④红毛草种子的发芽率在贮藏两年后开始显著下降(p<0.05),但在贮藏的第四年仍维持在一定的水平(11.1%),说明红毛草有较长的种子寿命;⑤红毛草种子发芽迅速,在发芽的第1天就开始萌动,发芽的高峰期出现在发芽的第2-3天。以上繁殖特性均与红毛草能够成为先锋植物密切相关。

A greenhouse pot experiment and a lab germination test were carried out to determine the re- productive strategy of Rhynchelytrum repens （ Willd. ） C. E. Hubbard. The patterns of resource allocation in R. repens under four planting densities and the seed longevity and germination characteristics of R. re- pens in a 4 - year period were investigated, respectively. Our results showed that ： （1）the total biomass, shoot biomass, root biomass and root-shoot biomass ratio of R. repens under low planting densities were significantly （p 〈 0.05 ） higher than those under high planting densities, however, a contrasting pattern was observed for flower biomass; ~） the values of reproductive effort of R. repens under high planting densities were significantly （p 〈 0. 05 ） higher than those under low planting densities, indicating that R. repens tends to allocate more resources to reproductive organs in situations of limited resources; （3） the germination rate of R. repens seeds were significantly （p 〈0.05 ） reduced by the high temperature （45℃ ）, yet the relative high germination rate （30. 2% ） recorded at the high temperature indicated the tol-erance of R. repens to high temperatures; （4）the germination ability decreased significantly （p 〈 O. 05 ） in seeds stored for 2 years, however, the germination rate （ 11.1% ） in seeds stored for 4 years showed that the seeds can retain their viability over a relatively long period of time ; （5） R. repens showed fast germina- tion, specifically, the seeds began to germinate on the first day of the germination test and most of them germinated during the second or third day of the germination test. It could be concluded that R. repens as a pioneer species in many extreme environments was likely attributed to its reproduction properties revealed by this study.