Study On Microspore Culture And Adventitious Bud Regeneration Of In Vitro Cytoledon In Chinese Cabbage

In order to establish an efficient technique system of isolated microspore culture in Chinese cabbage, ten F1 hybrids of Chinese Cabbage(Brassica campestris ssp.pekinesis) were used as the donor plant for isolated microspore culture. The factors affecting microspore embryogenesis was studied; In order to realize the anatomy basis of adventitious bud regeneration in Chinese cabbage, the tissues of adventitious bud regeneration of in vitro cotyledon were observed. The main results were as follows:1. The microspore embryogenesis capacity was very great different among these genotypes, 3 materials of 10 genotypes used got embryoid successfully, especially, Huayangbai reached the highest level with 4.4 embryos per bud.2. The suitable size of floral bud for microspore culture was different in different genotypes. The cytological observation showed that the suitable size of bud was 2.5~3.0mm and 2.0~2.5mm for Huayangbai and Shanqiubai for microspore culture respectively, in which there were the most microspores in the medium and late uninucleate. It also found that the pollen development within a single anther was not asynchrony in Chinese cabbage3.The frequence of microspore-derived embryos of Huayangbai, Shanqiubai and 05 za 42 were elevated when the floral bud pretreated at 4℃low-temperature for 1d. The same effect didn't occured on Jc-9, but it was also induced microspore-derived embry, so that this treatment can keep floral bud fresh for isolated microspore culture temporarily.4. The Medium NLN was more suitable to induce microspore embryogenesis in Chinese cabbage than Medium 1/2 NLN.5. Plant growth regulators had great effect on embryoid induction and development. 6-BA and 2,4-D can promote embryoid induction and their proper concentration was both 0.2mg/L together;NAA and TDZ can not increase the frequency of microspore-derived embryo.6. The effect of colchicine on in vitro microspore embryogenesis of Chinese cabbage were investigated with 6 genotypes. The response of microspore callus to colchicine was depended on genetype. The low concentration of colchicine(0.8mg/L) can promote microspore-derived callus forming in Chinese cabbage. 7. The cotyledons with petiole were used as explants from common Chinese cabbage Shanqiubai and orange-heading Chinese cabbage 06J28. Investigation was carried out on histological change during the process of in vitro shoot regenaration from cotyledons with petiole. It was found that the cortex and vascular parenchyma cells on petiole incision end were induced to start division at 2 ~ 3 days cultured, then the cells divide rapidly and form meristematic cells mass. the bud primordia were appeared from the cut section of petiole of Shanqiubai and 06J28 at 5 days and 6 days cultured respectively. The results of histological observation indicated that the shoot regenarates directly from the cut end of cotyledons with petiole.It was also observed that the individual shoot of Shanqiubai regenarated from internal callus and was endogenius.