| Calanthe, a perennial herb of Orchidaceae. It is about250native species. Calanthetsoongiana T. Tang et F. T. Wang is a orchid species endemic to China. C. tsoongiana, withbrilliant flower color and unique ornamental value,can act as parent to get more new strainsthrough the genus hybrid.The type specimen were collected from Zhejiang Province in1951.Since then, there is few reports about C. tsoongiana. it is essential to excute studies onbasic biology of C. tsoongiana. In this thesis, reproductive biology of C. tsoongiana wasstudied for the first time. The research in details focused on biological characteristics,microstructure of fruit, embryonic development, morphology and activity of seed, seedgermination. Main conclusions are presented as follows1. Biological characteristics of C. tsoongianaC. tsoongiana thrive in rich, high humidity and well-draining areas. C. tsoongiana couldresist the temperature below0°C and maintain evergreen.Each genets had multiple ramets. Ithad both sexual and asexual reproduction and the asexual reproduction played thepredominante role. The population came into bloom from March to April and the floweringspan among populations was approximately19days. The average life span of one single flowerwas8.14days. Fruit-bearing rate of C. tsoongiana was low under field conditions,but couldattained90%after artificial pollination.In the first3flowering days fruit-bearing rate of C.tsoongiana achieved100%, and reduced in the fourth day and fifth day.2. Studies on anatomical development and fruit growth of C. tsoongianaThe first40days is the fastest growth period of C. tsoongiana capsules. C. tsoongiana istricarpellate, showing a pattern of six valves in cross section: three fertile and three sterile. Thesix half-carpels remain joined at the apex. The increase in the fruit diameter results mainlyfrom cell division between valves and the increased volume of mesocarp cells and not from thenumber of cell layers. The volume of exocarp and endocarp remain unchanged in different development stages. In the mature fruit of C. tsoongiana,only a few cells show parietalthickening,The precursor cells of the dehiscence line become lignified on their cell wall inmature fruits, the fertile and sterile valves contract in opposite directions, resulting in alongitudinal rupture.3. Ovule development and seed formation of C. tsoongianaC. tsoongiana ovule primordia began to differentiate from placenta after pollination. Theovule was anatropous, bi-integument and tenuinucellar. Development of embryo sac waspolygonum type. Ovules development were not synchronized even in the same fruit.The firstzygote division was unequal, producing a basal cell and a terminal cell. The basal cell gave riseto the suspensor and it did not participate in the formation of embryo proper. The suspensordegenerated at the late stage of the embryo development. Terminal cell gave rise to embryoproper. Development of embryo was caryophyllad type.The shape of mature seed likedspindle.It consisted of globular embryo,endopleura and episperm.Endopleura, epispermdeveloped from inner tegument and outer integument seperately.4. Seed germination of C. tsoongiana4months after pollination, germination rate of C. tsoongiana seeds was the highest.120dsafter sowing,embryos of C. tsoongiana seeds began to expand, and break through the seed coatto form the protocorm eventually. The germination rates varied considerably on differentculture mediums. VW medium had the highest germination rate. Adding coconut juice, couldpromote germination of C. tsoongiana.On the contrary, adding bananas could inhibitgermination of C. tsoongiana. |
