Pollination Biology Of Rosa Laevigata, Camellia Fraterna And Rhododendron Ovatum In TianTong Forest Park

Evergreen Broad-leaved Forest is widely distributed in the subtropical east of China. As the important tree species in shrubs and treelets, Rosa laevigata, Camellia fraterna and Rhododendron ovatum have extremely important function to maintain ecosystem's stability and community's structure. The reproductive biology of main tree species have district impact on ecosystem's stability. As the integrant contents in pollination biology, floral structure, sex expression, foraging behavior and visitation rate of flower visitors on inflorescences have important influences on successful pollination. Based on field observation and experiment, we debate the cooperration between the plants and their visitors and the adaption between the biology and the environment. The main results are provided as follows:1 Pollination biology of Rosa laevigataObservations of visiting species and behavior of Rosa laevigata were made in this essay. Seven species were recognized as the flower visitors. Visiting most frequently seen were arranged in Hymenoptera, such as bees and Coleoptera, such as beetles. During the various blooming days, the visiting frequencies of floral visitors in inflorescences were greatly different. Usually, the visiting peak was from 10:00 to 11:30; while the number of visitors decreased from 14:00. Field observation further showed that cloudy and rainy weather had important influences upon the numbers and frequencies of floral visitors. There was a striking difference in the duration time of visitors on the flowers in a day. Treatments of emasculation and perianth removal showed that the stamina had important effect on attracting visitors.2 Pollination biology of C.fraternnaFlowers were light pink and white coloured. The life span of one flower was usually about seven to eight days. On the first day when C. fraternna was in bloom or the second day after blooming, the pollen grains shed. The viability of pollen lasted for over eight days. Pollen viability and life-span of C. fraternna was evaluated by TTC (2, 3, 5 - triphenyltet razolium chloride) test, its stigma receptivity was estimated by benzidine - H₂O₂ method. The pollen viability declination of C. fraternna at edge of forest was slow from the first day to the fifth day, while that of those in forest keep slow all the time. One day after blooming, most of stigmas split open and had receptivity. The more the canopy closure was, the later the stigma receptivity began.