濒危植物长柄双花木自然种群结实的花粉和资源限制  

Pollen and resource limitations to lifetime seed production in a wild population of the endangered plant Disanthus cercidifolius Maxim. var. longipes H.T.Chang (Hamamelidaceae)

作　　者：肖宜安[1] 曾建军[1] 李晓红[1] 胡文海[1] 何平[2] 

机构地区：[1]井冈山师范学院生命科学学院,江西吉安343009 [2]西南师范大学生命科学学院,重庆400715

出　　处：《生态学报》2006年第2期496-502,共7页Acta Ecologica Sinica

基　　金：国家自然科学基金资助项目(30560025;30560089)~~

摘　　要：长柄双花木(DisanthuscercidifoliusMaxim.var.longipesH.T.Chang)只零星分布于湖南、江西和浙江等省的少数县,已处于濒危状态。通过对其野外自然种群试验,研究了花粉和资源的有效性对雌性生殖的影响,并进一步探讨了长柄双花木“花多果少”的生殖机制。结果表明:不同来源的花粉对长柄双花木结果率及结籽率均产生显著影响。花粉来源而不是花粉数量对长柄双花木结实存在显著影响。自然条件下,长柄双花木“花果转化率”约为54.8,“胚珠种子转化率”约为83.19。施肥处理有利于花芽发育,可使植株花芽败育率明显下降,开花比例升高;同时座果率和结籽率均显著提高,而果实败育率则显著降低。随剪除叶片量的增加,结果率明显降低,但果实败育率在处理间无显著差异;剪除弱小枝条及病虫枝后,个体总开花数虽有所下降,但是结果率和结籽率均显著提高。去除花后,长柄双花木平均单果重、单粒种子重均显著降低。营养水平的时空异质性使自然种群结籽率受到资源和花粉的限制;补充资源可以通过增强花对传粉者的吸引而间接影响传粉。长柄双花木自然种群的坐果率极低,而且存在严重的“大小年”结果现象,不同的因子可能对其低水平坐果率产生相互作用。选择性败育、子房供应和雄性功能假说似乎是长柄双花木“花多果少”的生殖策略的最合理解释。Disanthus cercidifolius Maxim. var. longipes H.T. Chang, a plant species that only occurs in a few counties in Hunan, Jiangxi and Zhejiang Provinces and with relatively small numbers of individuals, is ranked as a 2^nd Class endangered species for conservation in China. we have studied the effect of pollens and resource available to the female reproduction, and the reproductive mechanism of ＂excess flowers production, but few fruit set＂ in Disanthus cercidifolius Maxim. var. longipes H.T. Chang was discussed. The results are as follows： Pollens which had from different sources have significant effect on fruit set and seed set of Disanthus cercidifolius Maxim. var. longipes H.T. Chang. The pollen source rather than pollen numbers effected significantly on the reproduction of this species. In wild populations, producing one fruit needs about 54.8 flowers, and one satiation seed needs about 6.6 flowers or 83.19 ovules. Fertilizing was propitious to the flowers developing, and after fertilizing, the abortion rate of flower bud was decreasing, but the flowering rate increasing. The fruit set and seed set also was significantly increasing, while abortion rate of fruit was significantly decreasing. With the increasing percentages of cutting leaves, the fruit set decreased, but the abortion rate of fruit was not significantly differentiation among what treatments. After cutting the puny branches, broken and insect pest branches, the flower number appeared a little decreasing, but the fruit set and seed set all increased significantly. After removing some flowers, the fruit set was calculated with respect to the number of flowers remaining after the treatment increased with increasing of percentages of flower removal, whereas fruit set calculated with respect to the initial number of flowers remained constant, and the mean weights of per fruit and per seed all decreased significantly. Sufficient spatial or temporal heterogeneity in nutrient levels might allow limitation of seed set by resources and pollen in a

关 键 词：花粉限制 资源限制 补充授粉 结实率 长柄双花木 

分 类 号：Q948[生物学—植物学]