野生荞麦细柄野荞麦的繁殖生物学特性研究

Reproductive biological characteristics of wild Fagopyrum gracilipes

关键词:  细柄野荞麦, 繁育系统, 传粉生物学, 种子, 繁殖

Key words:  Fagopyrum gracilipes, breeding system, pollination biology, seed, reproduction

摘要:

该研究通过野外观察和人工控制实验相结合的方法,从开花动态、花部基本特征、繁育系统、传粉生物学及种子性状等方面对荞麦属(Fagopyrum Mill.)植物细柄野荞麦(Fagopyrum gracilipes)的繁殖生物学特性进行了探究,并分析了各性状对其繁殖的贡献。结果表明:在贵州威宁,细柄野荞麦的花果期常为每年的6—10月,单花序和单花的花期分别为13～21 d和1～3 d。花较小,直径为(3.99 ± 0.12)mm,花柱和花药高分别为1.30和1.65 mm,花直径与花被片长和花被片宽呈显著正相关,花柱高与花药高呈极显著正相关。细柄野荞麦花粉胚珠比为371 ± 16.40,杂交指数为2,套袋实验显示其自交、异交亲和,表明其繁育系统为兼性自交,部分异交亲和。细柄野荞麦的访花昆虫较少,主要为膜翅目(Hymenoptera)、双翅目(Diptera)和鞘翅目(Coleoptera)7个科的9种昆虫,食蚜蝇科(Syrphidae)昆虫是其主要传粉昆虫。细柄野荞麦果实存在有翅和无翅两种类型,有利于其适应不同的传播方式,种子较小,千粒重为(1.05 ± 0.04)g,萌发率较低,播种后30 d的累积萌发率为(19.60 ± 2.14)%,但萌发整齐,主要集中在前5 d。综上所述,细柄野荞麦灵活的繁育系统为其产生大量种子提供了保障,多样的果实传播方式和整齐的种子萌发特性为其占据更广阔的生境成为群落优势种创造了基础。

Abstract:

We investigated reproductive traits of Fagopyrum gracilipes such as flowering dynamics, floral basic characteristics, breeding system, pollination biology and seed characteristics by field observations and artificial control experiments, also discussed their contribution to the reproduction of F. gracilipes. The results showed that F. gracilipes flo-wered and fruited during June to Octomber in Weining, Guizhou Province. The flowering lifespans of a single inflorescence and flower were about 13-21 d and 1-3 d respectively. The flower was small with the diameter of(3.99 ± 0.12)mm, the height of the style and anther was 1.30 and 1.65 mm respectively, the floral diameter had significant positive correlation with tepal length and tepal width(P < 0.05), the height of the style had highly significant position correlative with the height of anther(P < 0.01). The pollen-ovule ratio of F. gracilipes was 371 ± 16.40, its out-crossing index was 2, and the results of bagging experiments showed it was self- and cross-compatible, which suggested that the bree-ding system of F. gracilipes was facultative selfing, partial crossing-compatible. The main floral visitors were nine insects of Hymenoptera, Diptera and Coleoptera, the insects in family Syrphidae were its main pollination insects. The fruits of F. gracilipes included two types with and without wings which was helpful for its adaption to different spread manners, its seeds were smaller with the thousand seed weight of(1.05 ± 0.04)g, and had low but orderly germination rate with accumulated germination rate of(19.60 ± 2.14)% 30 d after sowing. It could be concluded that the flexible breeding system provided security for mass seeds production of F. gracilipes, various fruit spread manners and orderly seed germination characteristics created the basis for its colonizing vast habitats and becoming the dominant species in the community. The results can provide important reference for revealing the reproduction mechanism of F. gracilipes and buckwheat breeding.