The consequences of demand-driven seed provisioning for sexual differences in reproductive investment in Thalictrum occidentale (Ranunculaceae)

Many iteroparous angiosperms may benefit from flexible annual resource allocation in response to variable reproductive opportunities induced by external conditions. If maximal reproductive investment is fixed, lack of reproductive sinks would cause resource redistribution to other sinks. Alternatively, reproductive investment may vary depending on the demand of reproductive sinks, changing source-sink relations. In particular, differential responses by males and females to the demands of flower and seed production may cause sexual dimorphism. We assess the occurrence of demand-driven seed allocation by females and its implications for sexual differences in reproductive investment, including the dynamics of mass and carbon allocation and the physiological cost of reproduction, for a dioecious, perennial herb, Thalictrum occidentale. We specifically quantified allocation responses to partial defoliation, which reduced current resource supply, and partial flower/fruit removal, which reduce...诸多多次结实被子植物（iteroparous angiosperms）可通过灵活的年度资源分配策略，响应外界环境诱导的生殖机会波动，从而获益。若将最大生殖投入设为固定值，生殖库匮乏将导致资源向其他库重新分配；反之，生殖投入可随生殖库的需求动态调整，进而改变源-库关系。尤为关键的是，雌雄个体对开花与种子生产需求的响应差异，可能引发雌雄异型现象（sexual dimorphism）。本研究以雌雄异株（dioecious）多年生草本植物北美唐松草（Thalictrum occidentale）为研究对象，旨在探究雌性个体的需求驱动型种子分配现象，及其对生殖投入性别差异的影响，包括生物量与碳分配动态以及生殖的生理成本。本研究还专门量化了植株对部分去叶（降低当前资源供给）与部分花/果摘除（减少……）的分配响应。