Pollination Biology And Germination Characteristics Of Cleisostoma Paniculatum

Cleisostoma paniculatum (Ker-Gawl.) Garay is a high ornamental and medicinal value orchid species, which existed in low elevation forest. However, with the development of mountain tourism, exploring of ornamental value and medicinal value, its wild resources was extremely distured, and the population decresed sharply. As result, it has become an endangered wild plant. Therefor, it is urgent that its resource should be protected immerdately. In order to put forward effective measures of protection, we need to master the pollination biology and seed germination characteristics of C. paniculatum. In this paper, we do some research about its flowers, pollination, fruits, germination and cryopreservation by using the methods of wild shooting, artificial pollination, and tissue culture. The main results are as follows:(1) The flowering period of C. paniculatum is from 18th June to 12th Augest. The overall population’s blooming time lasts 44-55 days, and sigle flower’s blooming time lasts 3-5 days. The color of petals changed a little in the yellow group from an early opened flower to a blooming flower, but the color of labellum and spur changed from green-yellow group to yellow group, which changed more than petals. The spur with nectar appeals to the Megachile sculpturalis for pollination, and the pollination mechanism of C. paniculatum is a typical paid. There is a positive correlation between the visiting frequency of M. sculpturalis and the number of flowers and the ambient temperature. On the contrary, there is a negative correlation between the visiting frequency of M. sculpturalis and the ambient humidity.(2) The pollen viability of the first day opened flower is the higest (84.73%), and the stigma receptivity of the first day is the strongest. Both of them are decreased with the flowering times, and the stigma of flowers blooming for 3 days has no receptivity. The value of outcrossing index (OCI) and pollen/ovule (P/O) are 4 and 47.7, respectively. The fruits by illegitimate pollination and cross-pollination are impactful. The above results show that the breeding system of C. paniculatum is outcrossing, self compatible, requiring pollinators, and doesn’t have the phenomenon of apomixis and automatic self pollination.(3) The seed viability of 180-day old fruits is the highest (95.69%). In the orthogonal experiment of seed germination the effect of basic medium, Hua Bao No.l, NAA, and 6-BA decreased in turn. The optimum medium for seed germination is 1/2MS+NAA 0.5 mg·L-1+6-BA 2.5mg·L-1+Hua Bao No.11g·L-1+Agar 8g·L-1+Saccharose 25g·L-1+ Activated Charcoal 1 g·L-1,pH5.8.(4) The seed germination rate of seeds whose moisture content is 5.21% reaches the maximum value after 60 minutes teeated in protection of vitrifiable solution 2, (PVS2) in the seed cryopreservation experiments. The germination rate of seeds treated in cryopreservation is 2.62% higher than that of seeds without cryopreservation. The results show that the germination rate of dried seeds treated with PVS2 can be effectively improved.