三种同域分布喉毛花的繁殖分配

Reproductive allocation of three sympatric Comastoma(Gentianaceae)species

关键词:  喉毛花属  繁殖分配  生活史  个体大小效应  异速关系  青藏高原

Key words:  Comastoma  reproductive allocation  life-history  size-dependent effect  allometric relationship  the Qinghai-Tibet Plateau

摘要:

以青藏高原高寒草甸中三种同域分布的喉毛花为研究对象,通过比较三个种的植株性状和繁殖分配,探讨繁殖分配的种间差异及其与植株个体大小的关系。结果表明:(1)三个种的植株高度、顶花大小和单株花数目、繁殖分配均存在种间差异,这可能与其各自的交配系统和具体的生境以及相应的生活史对策有关;(2)在三种喉毛花中,投入到营养器官和繁殖器官的绝对资源量均呈显著正相关,未检测到植株生长和繁殖间的权衡关系;(3)三个种的个体大小与繁殖器官生物量均呈显著正相关,而与繁殖分配均呈显著负相关,这表明个体越大,繁殖投入越高,而繁殖分配越低,与以往研究结果一致,这可能是由于繁殖分配与个体大小之间存在异速关系。

Abstract:

Resource allocation strategy is central to plant life-history theory and thus receive extensive attention of ecologists and evolutionists. However,there are few research about the resource allocation strategies of sympatric species of the same genus. We studied the plant traits and reproductive allocation of three sympatric Comastoma species which are all alpine annual herbs of the Qinghai-Tibet Plateau. Our results were as follows:(1)there were significant differences in plant height,flower number every plant,top flower size and reproductive allocation among three species due to their different mating systems,habitats and life-history strategies;(2)in all three species,there was positive relationship between resource allocation of vegetative organs and reproductive organs,and no trade-off between vegetative growth and reproduction was found;(3)the reproductive investment increased but the proportion of reproduction(reproductive allocation)decreased with increased individual size,which was consistent with the previous conclusions,indicating size-dependency of reproductive allocation and this might be resultant from the allometric relationship between reproductive allocation and individual size.