Evolution of Androdioecy

在一个物种中维持雄性植物和同时拥有雄性和雌性生殖器官的植物被称为雄雄异雄。然而，一些植物科学家认为，理论上这种生殖系统很难在自然界中存在。事实上，在目前的研究之前，没有一个雄性异株物种被记录在案。Rieseberg博士和他的同事们最近证明了植物物种Datisca glomerata是雄性异株的，并提出了确定这种生殖系统是如何起源和如何维持的。由于柽柳是目前已知的唯一雌雄同株的植物，它将为植物生物学领域的研究提供一个模式系统。利用这个模型系统可以解决一些基本的科学问题：1)植物中不同的生殖系统是如何进化和维持的？2)一种生殖系统如何改变为另一种？3)这种变化的遗传或环境基础是什么？这些问题对基础植物生态学家来说很重要，但也与试图改进现有作物或试图开发新的农业重要植物的育种家有关。例如，一个既有雄性植物又有雌性植物的物种作为农作物是相当低效的，因为只有50%的植物会结果。了解生殖系统的进化对维持生物多样性也很重要。生殖系统的变化会改变物种的稳定性，并可能导致它们的灭绝。

The maintenance of male plants and plants possessing both male and female reproductive organs in a single species has been termed androdioecy. However, several plant scientists have suggested that it is theoretically very difficult for this reproductive system to exist in nature. In fact, not one androdioecious species had been documented prior to current work. Dr. Rieseberg and his colleagues have recently demonstrated that the plant species Datisca glomerata is androdioecious and propose the determine how this reproductive system originated and how it is being maintained. Because Datisca glomerata is the only plant species known to be androdioecious, it will provide a model system for studies in the field of plant biology. Basic scientific questions can be addressed using this model system: 1) how do different reproductive systems in plants evolve and how are they maintained? 2) how can one reproductive system be changed to another? and 3) what is the genetic or environmental basis for this change? These questions are important for basic plant ecologists, but are also relevant to breeders trying to improve existing crop plants or trying to develop new agriculturally important plants. For example, a species that has both male and female plants is quite inefficient as a crop plant because only 50% of the plants will bear fruit. Understanding reproductive system evolution is also important for the maintenance of biodiversity. Changes in reproductive system can alter species stability and potentially lead to their extinction.