二态混合交配系统的适合度优势及其维持机制研究进展

由开花受精花(chasmogamous, CH)和闭花受精花(cleistogamous, CL)构成的二态混合交配系统植物有着特殊的繁殖策略, 对其进行深入研究有助于理解植物交配系统的维持机制、进化趋势以及植物对环境变化的应对策略。本文综述了国内外关于CH-CL系统两型花研究的文献资料, 包括非生物因素和生物因素对该繁育系统两型花的生长、发育及相对比例的影响, 两型花的维持机制及进化意义, 阐明了CH-CL系统的研究现状及科学问题, 重点评述了基于近年来对CH-CL系统研究成果的新认识。作者提出, 精确地检测两种花型的后代在异质生境下以及在生活史的不同阶段的适合度差异是十分必要的; 微环境(种子的散布模式及位置效应)对两型花种子萌发和子代生长发育的影响非常重要; 两型花表达的时空差异(即开花模式及对异质生境的敏感性差异)的表达机制可能与内源激素的水平变化相关; 对于多年生具CL系统植物来说, 不同性质、不同来源的后代在居群中的分布式样及对居群遗传结构的影响很可能是该系统维持的重要机制。因此, 深入研究和科学认识二态混合交配系统对认识整个植物界繁育系统的进化有十分重要的意义。

Fitness advantage and maintenance mechanisms of dimorphic mixed- mating plants

Plants that have a dimorphic mixed-mating system consisting of open chasmogamous flowers (CH) and closed cleistogamous flowers (CL) have special reproductive strategies. Further research on CH-CL mating systems can help us understand the maintenance mechanism, evolutionary trends and strategies of plants in response to environmental change. This paper reviews existing literatures on dimorphic flowers (dimorphic mixed-mating system) of CH-CL systems including the effects of different abiotic and biological factors on the growth, development and relative proportion of flowers. It also reviews the maintenance mechanisms and evolutionary significance of dimorphic flowers. Recent researches of CH-CL system and remaining scientific questions are outlined and the new understanding of CH-CL systems based on recent research is reviewed. We suggests that it is necessary to accurately detect the differences between the progeny of the two flower forms in heterogeneous habitats and at different stages of life history. The microenvironment (separation pattern and location effect of seeds) is also identified as being very important for seed germination and the growth and development of the two flower types. Additionally, the expression mechanism of the spatial and temporal differences in flower types (the pattern of flowering and sensitivity to heterogeneous habitats) may be related to changes at the levels of endogenous hormones. It has been said that the distribution of populations of different natures and different sources, and the impact on the genetic structure, is likely to be an important mechanism for the maintenance of the system. Therefore, in-depth research and scientific understanding of dimorphic mixed-mating system may be of great significance for understanding the evolution of the entire plant reproductive system.