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开花植物延迟自交的研究进展

花匠小妙招
2025-01-02 02:13

摘要：

延迟自交是植物在单朵花开花末期主动自花授粉的一种繁殖方式。为了补充及完善植物进化和传粉生物学研究的综合数据资料,笔者概述了延迟自交的发生途径、试验研究方法、“两全其美”繁殖保障假说等方面的进展,探讨了其适应性意义,并对今后的研究方向提出了建议。目前,延迟自交现象广泛发生在43科61属74种植物中,其中,52种植物的发生途径是单一的,22种植物由两种途径共同作用。在单一途径中,柱头弯曲引起的延迟自交最为常见;不完全雌雄异熟和雌雄异位减小两种途径共同作用促进的延迟自交最为常见。对延迟自交的观察,多采用宏观传粉生物学手段,少有研究将宏观传粉生物学与遗传学手段相结合为延迟自交的发生提供最严谨的证据。延迟自交的繁殖保障假说表明,植物在优先保障异交进行的前提下,当传粉环境不可预测时,延迟自交能为植物的繁殖成功提供保障,被认为是结合了自交和异交优点的“两全其美”的交配系统。此外,对于少胚珠物种,昆虫单次授粉后即可充分授粉;为节约植物资源,还可阻止延迟自交的发生。

关键词: 开花植物, 延迟自交, 繁殖保障, 近交衰退, 适应性机制

Abstract:

Delayed autonomous self-pollination or delayed selfing is a reproductive way of autonomous self-pollination that occurs at the end of cross-pollination of a single flower in flowering plants. To complement the comprehensive data base of plant evolution and pollination biology, we provide a review of progress in the occurrence pathways, experimental research methods, and the “best of both worlds” reproductive assurance hypothesis of delayed selfing. We also discuss the adaptive significance of delayed selfing and suggest future research directions. The delayed selfing is present in 74 angiosperm species, and widely distributed in 61 genera and 43 families, of which 52 species occur by a single pathway and 22 species by two pathways. In a single pathway, the style curvature is the most common to cause the delayed selfing. Incomplete dichogamy and reduced herkogamy are the most common pathways promoting the delayed selfing occurrence. Observations of delayed selfing have mostly been done through pollination biology, and few studies have combined pollination biology with genetics to provide the most rigorous evidence for the occurrence of delayed selfing. The reproductive assurance hypothesis of delayed selfing suggests that it prioritizes securing cross-pollination and can aid in the reproductive success of plants when the pollination environment is unpredictable. Therefore, the delayed selfing is considered the “best of both worlds” mating system that combines the advantages of selfing and outcrossing. In addition, for ovule-less species, plants have sufficient prior pollination and fertilization after a single visit by insects, which also prevents the occurrence of delayed selfing to save plant resources for other purposes.

Key words: flowering plant, delayed autonomous selfing, reproductive assurance, inbreeding depression, adaptation mechanism

中图分类号:

S718

Q941