被子植物性系统及其可塑性

繁殖是生物适合度的最终表现,有性繁殖相关性状的多态性极大地促进了物种分化和生物多样性的维持,并影响着植物对环境变化的响应。在种群水平上,被子植物的花有雌花、雄花和两性花三种性表型,三种性表型在种群中的分布和频率即定义了种群的性系统。被子植物的性系统包含植物影响性分配和交配的相关特性,决定着雌配子、雄配子在种群中的频率、交配机会及交配方式,是有性繁殖的关键性状,在被子植物中表现出丰富的多态性,在种群水平上分为性单态和性多态两大类。性单态为被子植物的古老性状,而性多态在100多个被子植物科中独立进化产生。被子植物性系统多态性及其变化机理一直是进化生物学与生态学的热点问题之一。该文以种群水平的性多态为对象,总结了被子植物性系统的类型、表达的遗传基础、分布频率,以及遗传因子、非生物环境和交配环境对性系统表达和性分配的影响。

Sexual systems and labile sex expression in angiosperms

Reproduction defines the fitness of organisms. Surviving and successful adaptation by angiosperms to our changing world depends on their sexual reproduction. Three sexual phenotypes are found in angiosperms at population level, i.e. female flower, male flower and hermaphrodite. The composition and frequency of these three sexual phenotypes in population define the population sexual system. Variation and evolutionary flexibility of key traits associated with sexual systems are also often regarded as major drivers of the divergence of plant lineages and the maintenance of biodiversity, which shape mating chances and mating patterns of male and female gametes in plant populations. Intraspecific sexual system diversity is common in angiosperms, and can be found among flowers or populations. Sexual systems in angiosperms can be divided into two classes, i.e. gender monomorphism and gender polymorphism at population level. Gender monomorphism is an ancient trait,however gender polymorphism has evolved independently in more than 100 angiosperm families. It is believed that sexual systems and sex allocation are highly sensitive to environmental changes and the ways that sexual expression responds to changes in abiotic and biotic environments is a major current theme in evolutionary biology and ecology. Here, we discuss within-population polymorphisms in sexual systems and review the frequencies of different sexual systems in angiosperms from the perspective of how sexual expression and sex allocation respond to genetic constrains, abiotic environments and mating environments, aiming to encourage more studies in this area.