两种生境中薇甘菊种群的生物量生殖分配

Reproductive Allocation of Biomass in Mikania micrantha Populations from Two Habitats

于2004年薇甘菊(Mikania micrantha)生殖阶段的现蕾期至种子成熟期,从种群和构件水平上研究了两种生境(林窗和开阔地)中薇甘菊种群的生物量生殖分配。结果表明,在生殖生长过程中,两种生境中的种群用于营养生长的生物量分配均占有绝对优势,而生殖生长的波动相对较大。花序的生物量分配(RA)总体上均呈现由低到高的变化趋势。在不同时期,林窗薇甘菊种群的营养枝生物量分配均小于开阔地,而除了种子形成期和种子成熟期以外的其它各个时期,林窗中生殖枝的生物量分配均大于开阔地,林窗中花序的生物量分配均显著大于开阔地。表明薇甘菊能有效权衡其在不同生境中的繁殖策略,开阔地中的薇甘菊种群的繁殖策略倾向于克隆繁殖,而林窗生境中薇甘菊种群则相对更倾向于有性生殖。

Reproductive allocation of biomass in Mikania micrantha H.B.K.populations from two different habitats,forest gap and open land,was studied at our field station in Dongguan City,China.From November to December 2004,samples were taken from blooming plants of M.micrantha at six different floral stages：bud emerging stage（Nov.1st）,bud stage（Nov.12th）,middle period of bud spreading（Nov.20th）,blooming stage（Nov.29th）,seed forming stage（Dec 9th）,and seed maturation stage（Dec.24th）.Reproductive allocation of biomass along with their relationship to the living environment from the two different habitats was examined at the modular and population levels.The results showed that during M.micrantha reproduction phases,both populations allocated predominant biomass to their vegetative growth,while the biomass allocated to reproductive growth displayed a relatively significant fluctuation.With ongoing reproductive phases,biomass allocated to inflorescence（RA）increased as a whole.During the six stages in our study,biomass allocated to vegetative shoots in the gap population was significantly less than that in the open land population,while the opposite occurred for reproductive shoots,except at the last two stages.Biomass allocated to inflorescence in the gap population was significantly greater than in the open land population through all the six stages.The results demonstrate that M.micrantha populations in gaps tend to use cloning as its reproduction strategy,while the population in open land uses sexual reproduction.