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 C...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 increasing attraction of the flowers to pollinators.There were very low fruit and seed sets in natural populations of Disanthus cercidifolius Maxim.var.longipes H.T.Chang.Different factors may have interacted to effect a low fruit set.A joint adoption of the“selection abortion hypothesis”,“ovary reserve hypothesis”and“male function hypothesis”seems to be the most likely explanation for the reproductive strategy of“excess flowers with few fruit sets”in Disanthus cercidifolius Maxim.var.longipes H.T.Chang.展开更多
Effects of treating with 0.05, 0.10, 0.20 and 0.40 mg·g-1 NAA for 3 h on cutting regeneration of Disanthus cercidifolius var. longipes H.T.Chang were studied. The results indicated that effects of different conce...Effects of treating with 0.05, 0.10, 0.20 and 0.40 mg·g-1 NAA for 3 h on cutting regeneration of Disanthus cercidifolius var. longipes H.T.Chang were studied. The results indicated that effects of different concentrations of NAA on biological indexes of cutting regeneration weremarkedly different except plantheight and ground diameter.With0.1 mg·g-1 NAA solution treating for 3 h, individual biomass, root biomass, total length of root, root number, new leaf number and total length of new branch increased obviously.展开更多
基金This paper was supported by the National Natural Science Foundation of China(Grant Nos.30560025,30070080).
文摘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 increasing attraction of the flowers to pollinators.There were very low fruit and seed sets in natural populations of Disanthus cercidifolius Maxim.var.longipes H.T.Chang.Different factors may have interacted to effect a low fruit set.A joint adoption of the“selection abortion hypothesis”,“ovary reserve hypothesis”and“male function hypothesis”seems to be the most likely explanation for the reproductive strategy of“excess flowers with few fruit sets”in Disanthus cercidifolius Maxim.var.longipes H.T.Chang.
文摘Effects of treating with 0.05, 0.10, 0.20 and 0.40 mg·g-1 NAA for 3 h on cutting regeneration of Disanthus cercidifolius var. longipes H.T.Chang were studied. The results indicated that effects of different concentrations of NAA on biological indexes of cutting regeneration weremarkedly different except plantheight and ground diameter.With0.1 mg·g-1 NAA solution treating for 3 h, individual biomass, root biomass, total length of root, root number, new leaf number and total length of new branch increased obviously.
