我国特有植物菱叶凤仙花的繁育系统及其与同属植物的比较

Breeding System of Impatiens rhombifolia Endemic to Chinaand Its Comparison with Other Congeneric Plants

菱叶凤仙花(Impatiens rhombifolia)是我国特有植物,研究其田间种群的繁育系统并同其他同属植物进行比较,有助于阐明该种传粉过程、花部进化以及物种狭域分布的特有原因。通过对菱叶凤仙花田间种群的开花物候、花部特征、传粉者、花粉胚珠比、杂交指数、交配系统特性进行研究,发现菱叶凤仙花雄蕊先熟,传粉者为三条熊蜂(Bombus trifasciatus),盗蜜者为短头熊蜂(B.breviceps),其余访花者为中华蜜蜂(Apis cerana)、小豆长喙天蛾(Macroglossum stellatarum),花粉胚珠比约为11443,杂交指数为4。人工授粉实验中,不去雄套袋和去雄套袋的坐果率分别为5%和0,自然授粉、人工异交和人工自交的坐果率分别为86%、89%和76%。通过分析同属植物的繁育系统共性,发现包括菱叶凤仙花在内的36种凤仙花属植物均可异交,其中30%属于高度异交或专性异交,70%为自交亲和,自交亲和中有24%可以自动自交,只有1种凤仙花以自交为主不需要传粉者,且无近交衰退。总之,菱叶凤仙花是自交亲和的异交植物,具有低比率的自动自交能力,不存在无融合生殖,包括菱叶凤仙花在内的凤仙花属植物大多都以混合式交配系统为主,可以更好适应复杂多变的环境。

As Impatiens rhombijfolia is an endemic plant in China,the study on the breeding system of its field population and the comparison with other plants of the same genus can help to elucidate the pollination process of the species,the evolution of the floral parts,and the reasons for the endemicity of the species narrow range of distribution.The study on the characteristics of the field populations of Impatiens rhombijfolia in terms of flowering phenology,floral characters,pollinators,pollen-ovule ratio,hybridisation index and mating system finds that the stamens of Impatiens rhombijfolia have the first maturity and the pollinators are Bombus trifasciatus;the pollen thief is B.brericeps and the rest of the flower visitors are Apis cerana and Macroglossum stellatarum;the pollen-ovule ratio is about 11443 and the heterosis index is 4.In the artificial pollination experiments,the fruiting rates of non-male bagging and de-male bagging are 5%and 0%,respectively;for natural pollination,artificial heterozygosity and artificial self-crossing,they are 86%,89%and 76%,respectively.The overall analysis on the breeding system commonality of the same genus shows that 36 species of Impatiens are all heterogamous,including Impatiens rhombijfolia;among them,30%are highly heterogamous or exclusive heterogamous,and 70%are autogamous;24%of the autogamous affinities can be automatically self-fertilised;only one species of Impatiens is mainly self-fertilised with no need for pollinators,and there is no inbreeding recession.In conclusion,Impatiens rhombijfolia is an autogamous heterogamous plant with a low rate of automatic self-compatibility and no fusionless reproduction,and most Impatiens plants,including Impatiens rhombijfolia,are based on a mixed mating system,so that they can better adapt to the complicated and variable environments.