Reproductive Biology Of Hetaeria Cristata(Orchidaceae)

Hetaeria cristata, is a perennial herb, belongs to Hetaeria of Orchidaceae. The wild populations of H. cristata was served as experiential, and reproductive biology research was carried out. The main research results are as follows:1. The flowering period of Hetaeria cristata is September(or October), and the inflorescence last 31 d, with 3-15 flowersin a inflorescence. Single flower blooming is for about 8-12 days, while two flowers on the same inflorescence flowering time is about 1 day. Flowers is small, half open, white. Sepals hairs is on the back, reddish brown, labellum white, shallow cystic at base. The flowering pollen vigor are very low(20-30%), in double lip dialogue rib orchid bud period, the early flowering stage, full bloom and fade, by the methods of TTC and benzidine- hydrogen peroxide method. The stigma can grant sexual activity also is extremely low, basic inactive.2. Natural conditions, the seed setting rate was 95%, the artificial crosspollination and pollinate the flowers of seed setting rate were 100%, emasculation bagging and emasculation bagged seed setting rate were 100%. These results suggest that under natural conditions, there is no automatic pollinate and insect pollination for the flowers, and speculated that the reproductive mode of apomixis.3. By observing the development process of embryo experiments showed that the ovary was composed of 3 carpels, one room, side form placentation the differentiation of ovule primordia, the ovule primordia eventually develop into the ovule. Ovules borne down ovule development to cuhk spore mother cell volume increase, divided into tetrad, the final function megaspore eight nuclear embryo sac by split to form not reduction. Its not taking the eggs of meiosis in the absence of fertilization, by way of parthenogenesis, develops into an embryo. In addition, we through the chromosome ploidy analysis found that the wild population of plants stem section with aseptic germination produce chromosome number is consistent, are all 24. Thus, we inferred that the reproductive way for diploid spore reproductive body without fusion.4. Take the natural mature and full of capsule on seed vigor and aseptic seeding. The study found that the soak time of 12 h reached the highest seed vigor. After 90 d after sowing, burley double lip orchid seed embryo swelled, and break through the seed coat to form the original bulb. The seeds on different culture medium and hormone combination germination rate difference was very big, and through the study found that the best kind of embryo germination was 1/2 MS + 20 mg·L-1 sugar +(1.0-1.5) mg·L-1 6-BA + 0.5 mg·L-1 NAA +6.8 g·L-1AGAR+ 1.0 g·L-1 activated carbon.