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 2nd 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 natural population, supplying resources may indirectly effect on pollination by increasing the attraction of the flower to pollinators. There were very low fruit set and seed set in natural populations of Disanthus cercidifolius Maxim. var. longipes H.T.Chang. Different facts may have interaction to its low fruit set. The selection abortion hypothesis, ovary reserve hypothesis and male function hypothesis seem to be the most likely explanations for the reproductive strategy of “excess flowers production, but few fruit set" by Disanthus cercidifolius Maxim. var. longipes H.T.Chang.