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鸢尾的花部结构及繁育系统特征

花匠小妙招
2024-10-23 21:15

摘要： 对鸢尾（Iris tectorum）居群的花部特征、授粉特性、繁育系统及访花昆虫行为等进行了研究。在自然条件下，鸢尾4—6月开花，群体花期约60 d，群体盛花期约30 d，集中在4月20日—5月20日，单株花期10 ~ 30 d，单花花期2 d。雄蕊短于花柱，花药紧贴花柱外侧，花药与柱头相差约3 mm，在花朵开放的整个过程中雌、雄蕊的相对位置不变。杂交指数OCI为4，P/O（花粉/胚珠比）为234.4，结合坐果率判断其繁育系统属于异交，部分自交亲和，需要传粉者。鸢尾高度特化的花部特征与黄胸木蜂（Xylocopa appendiculata）和长木蜂（Xylocopa tranquebarorum）的传粉行为相适应。人工授粉结籽率高于自然传粉，证实鸢尾自然条件下的有性繁殖系统受到花粉限制和缺少传粉昆虫的影响。

关键词: 鸢尾, 花部特征, 杂交指数, 花粉/胚珠比, 繁育系统, 花粉限制

Abstract: Field investigation was performed on the floral syndrome，pollination characteristics，pollinator behaviors and breeding system of Iris tectorum by continuous observations and analyzing data of out-crossing index，pollen-ovule ratio，fruit-set ratio and seed-set ratio. The results were as follows：Under natural conditions，the flowering stage of populations is about 60 days from April to June，and the majority of plants kept blooming in 20th April to 20th May. The flowering stage for individual plant was 10–30 days. The life span of a single flower was about 2 days. The stamen was closed to the lateral side of the petaloid style. The stamen was about 3 mm shorter than the style. The relative position between the stamen and style was always unchanged during the whole flowering stage. It showed that the breeding system was out-crossing，part self-compatibility，insect pollinator-dependent when comparing the results of pollination experiments with the results of out-crossing index and pollen-ovule ratio. The specialized floral structure was suitable for the behavior of the pollinator，Xylocopa appendiculata and Xylocopa tranquebarorum. Hand pollinations improved reproductive success，suggesting that sexual reproduction may be influenced by pollen limitation and less pollinators in nature.

Key words: Iris tectorum, floral syndrome, out-crossing index, pollen-ovule ratio, breeding system, pollen limitation

中图分类号:

S 682.1+99