Study On Pollination Biology Of Camellia Oleifera

Camellia oleifera is an important oil plant. The author studied pollination biology of C. oleifera in three populations during 2007 and 2008.The florescence of C. oleifera begins from October to January next year; but it differs from every single tree, that is about 20 days. The individual flower blooms about 4-5 days. The mean nectar volume of per flower is 145.40±24.89μL (n=30), with a sugar concentration of 23.13±1.03%, there are 17 kinds amino acids in the nectar and its concentration of 1.73%. The mean Pollen/Ovule (P/O) ratio is 17675.08±302.11 (n=20). The highest pollen viability was 71.0±0.056% after 8h of the flowering. The fertility rate of pollen was 93.97±1.62% (n=30). The stigma receptivity reached the highest rate on the second day after flowering. Andrena camellia and Colletes gigas of Hymenoptera are considered as the most effective pollinators, while flies and butterflies are casual visitors. Length of A.camellia is 9.28±0.25mm, and C. gigas 18.17±0.25mm. The attraction of pollen and nectar are both very strong to A. camellia and C. gigas. But there are no significant differences between them.Through the detection of breeding system, the measurements of C. oleifera out-crossing index and P/O, results revealed that C. oleifera is a kind of plant of self-incompatible, needing pollinators. We found that there were significant differences among different pollination treatments (such as opening-pollination, self-pollination and cross-pollination).The period to bear fruit of C. oleifera extends as long as one year. The young fruit begins to grow and swell in mid-March. April is the peak period of fruit drop, and the smallest fruit drop rate is in May, after then, the rate rises again in the flowing months.C. gigas nests on Granite soil which is weathered from granite. Their nests are distributed into many pieces, with a few square meters of each piece. The maximum density can reach to 50 holes per square. Nest depth ranges from 30～40cm to 60～70cm, usually 1～2 branches each nest. Most silk nests are built 15～30cm away from the mouth of the cave. There are 3～5 silk nests in each nest, only one larva in every silk nest.