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

作　　者：XIAO Yian HE Ping ZENG Jianjun LI Xiaohong HU Wenhai 

机构地区：[1]College of Life Sciences,Jinggangshan University,Ji’an 343009,China [2]College of Life Sciences,Southwest China Normal University,Chongqing 400715,China

出　　处：《Frontiers in Biology》2007年第4期437-442,共6页生物学前沿（英文版）

基　　金：This paper was supported by the National Natural Science Foundation of China(Grant Nos.30560025,30070080).

摘　　要：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 a relatively small number of individuals,is ranked as a second Class endangered species for conservation in China.We have studied the effect of pollen and resources available to female reproduction,and the reproductive mechanism of“excess flowers with low fruit set”in Disanthus cercidifolius Maxim.var.longipes H.T.Chang was discussed.Results are as follows:Pollen from different sources has significant effects on fruit set and seed set of Disanthus cercidifolius Maxim.var.longipes H.T.Chang.The pollen source rather than pollen numbers significantly affected reproduction of this species.In wild populations,producing one fruit needs about 54.8 flow-ers,and one satiation seed needs about 6.60 flowers or 83.19 ovules.After fertilizing,which was propitious to flower develop-ment,the abortion rate of flower buds was decreasing,but the flowering rate was increasing.The fruit set and seed set was also 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 shows no significant differentiation among treatments.After cutting branches that were puny,broken and insect-infested branches,the flower number seemed to be decreas-ing,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 heterogeneities in nutrient levels might allow limitation of seed set by resources and pollen in a natural population,while supplying resources may indirectly affect pollination by inc

关 键 词：pollen limitation resource limitation hand-pollination seed set Disanthus cercidifolius Maxim.var.longipes H.T.Chang 

分 类 号：Q94[生物学—植物学]