忽地笑的花部特征与蝴蝶翅膀传粉研究

Floral characteristics and butterfly wing pollination of Lycoris aurea

关键词:  忽地笑, 繁育系统, 传粉限制, 访花昆虫, 自交亲和性

Key words:  Lycoris aurea, breeding system, pollination limitation, flower-visiting insect, self-compatibility

摘要:

忽地笑(Lycoris aurea)为石蒜科石蒜属多年生草本植物,具有重要的药用和观赏价值,其花呈蜘蛛花型,具有高度外露的柱头和花药,可能代表了一种独特的传粉方式。为了探究这种传粉方式,该文对忽地笑的花部特征、繁育系统和传粉昆虫及其行为进行了研究。结果表明:(1)忽地笑的单花持续时间为(5.9±0.1)d,花粉胚珠比(P/O)约为2.3万; 单花展示存在雌雄异位现象,在开花前期花柱和花丝是分开的,两者之间的角度约为30°,在开花的中后期花柱逐渐向花丝移动,最终两者在同一条线上,但柱头比花药高2～3 cm; 柱头在整个花期都具有可授性。(2)繁育系统试验表明,忽地笑具有一定的自交亲和能力,但不具有主动自交能力,需要访花昆虫来传粉; 补充花粉显著提高了坐果率,证明存在花粉限制。(3)4种凤蝶是有效传粉者,由于忽地笑存在雌雄异位,在开花前期,凤蝶访花后翅可能接触到扁平的花药,在开花中后期凤蝶访花时后翅才可能碰触到柱头从而完成传粉过程。总体而言,该研究证明了忽地笑独特的花部特征可能与蝴蝶翅膀传粉相适应,同时也为忽地笑的保护和利用奠定了基础。

Abstract:

Lycoris aurea is a perennial herbaceous plant with important medicinal and ornamental values in the genus Lycoris Herb, the family Amaryllidaceae. The flower has a spider shape with highly exserted stigmas and anthers, which may represent a unique pollination type. In order to explore this type of pollination, we studied its floral characteristics, breeding system, and floral visitors and their behaviors. The results were as follows:(1)The single flower lasted(5.9±0.1)d and the pollen-ovule ratio(P/O)reached about 23 000. The flowers showed reverse herkogamy. On the beginning of flowering, the style and filaments were separated and the angle between them was about 30°. The style gradually moved towards the filaments in the middle and later stages and were finally on the same line with the stigma 2-3 cm higher than the anthers. The stigmas were receptive throughout the flowering period.(2)The breeding system test was self-compatible and bagged flowers cannot set fruit, indicating that pollinators were necessary for pollen transfer. Supplemental hand pollination significantly increased fruit production, indicating the existence of pollen limitation.(3)Four species of swallowtail butterfly were the effective pollinators. Due to the existence of herkogamy in L. aurea, on the beginning of flowering, their hindwings were likely to come into contact with the flattened anthers. Their hindwings might touch the stigma in the middle and later stages and thus the process of pollen transfer was accomplished. In conclusion, this study shows that the uqique floral characteristics of L. aurea are adapted for butterfly wing pollination and also will lay the foundation for its conservation and sustainable utilization.