种子异型性及其生态意义的研究进展

Review of research on seed heteromorphism and its ecological significance

种子异型性是指同一植株产生不同形状或行为种子的现象。根据异型种子在植株上的生长位置,种子异型性可划分为地上下结实性和地上种子异型性两类。此现象已在26科129属292种被子植物中报道。异型性种子植物主要分布于干旱半干旱区、荒漠和盐渍土地区等干扰强烈的环境,在菊科和藜科中最为常见,主要出现在一年生植物中。种子异型性在避免密集负效应、减弱同胞子代间的竞争、采取两头下注策略以适应时空异质性环境等方面具有重要的进化生态意义。该文系统总结了国内外种子异型性的研究工作,主要内容包括:1)种子异型性的概念、类型和种类,2)具有异型种子植物的生境和生活型,3)异型种子的生态学特性,4)种子异型性的理论模型,5)种子异型性的生态意义。在综述文献的基础上,对今后的研究进行了展望。针对国内外的研究现状,提出两点建议:1)系统调查具有种子异型性现象的植物种类,摸清其生物学特性;2)确定研究种子异型性现象的模式植物,从生态学、生理学和分子生物学等学科角度来研究种子异型性的个体发育机制及分子调控机理。

Seed heteromorphism is the production of seeds of different form or behavior by single individuals. According to the relative position of seeds on the plant, seed heteromorphism can be divided into amphicarpy and heterodiaspory. Seed heteromorphism has been reported in 26 families, 129 genera and 292 species of angiosperms. Most heteromorphic plants studied are annuals, often species in Asteraceae and Chenopodiaceae faced with stochastic environments such as arid, semiarid, desert and saline soil. Seed heteromorphism is generally considered to play an important role in escaping from the negative effect of crowding, reducing sib competition and adapting to environment by following bet-hedging strategy. We review and analyze recent advances in seed heteromorphism research, with emphases on 1） conception and types of seed heteromorphism and the species of the heteromorphic plants, 2） habitats and life types of the heteromorphic plants, 3） ecological characteristics of heteromorphic seeds, 4） theoretical model of seed heteromorphism and 5） ecological significance of seed heteromorphism. In addition, we discuss prospects for further research in this area and suggest 1） species with seed heteromorphism should be investigated and their biological characteristics should be studied and 2） the model plant of seed heteromorphism needs to be selected and ecological, physiological and molecular biological methods should be used to reveal the ontogenetic and molecular controlling mechanisms.