Techniques For Isolated Microspore Culture And Plantlet Regeneration In Hong Cai-tai

Twelve varieties and strains of Hong cai-tai (Brassica campestris L.ssp.Chinensis L.var.utilis Tsen et Lee.2n=2x=20) were used for the isolated microspore culture in Hong cai-tai. The research included influence factors on microspore embryogenesis, the methods of increasing the regeneration and radication of plantlets and the ploidy identification. The main results were as follows: 1. The effect of genotype and bud size on embryogenesisThere was a considerable variation in the capability of embryogenesis in different genotypes. Of the 12 experimental materials, 9 genotypes produced embryoids. Among them 2 materials 'b' and 'D' produced higher embryoid yield. The highest embryoid yield of 'b' per utensil reached 63 embryoids. Under the same experimental condition, difference in genotypes resulting in variation of the embryoid yield in Hong cai-tai, was one of most important reason. The cytological observation of pollen at different developmental stage of Hong cai-tai were undertook. The results showed the buds which size were 2.50～3.50mm and the ratio of petal to anther length was between 3/4 ～ 1/1 produced the most embryoid yield. The buds with the length of less than 2.0mm and more than 4.0mm gave no embryoids in the experiment. 2. The effect of different treatment on the induction of embryoidThe cool pre-treatment at 4℃ on flower buds had negative effect on the embryoid yield. With the prolonging of the cool pre-treatment time the embryoid yield reduced gradually. The embryoids reduced 11 from 69 per 30 buds with 1 day cool pre-treatment. After the buds treated 2 days with cool pre-treatment the embryoid yield reduced significantly. Fresh buds or buds treated 1 d with the cool pre-treatment for microspore culture was better.The magnitude of the response to the addition of 0.5g/L activated charcoal to the microspore culture media varied with different genotypes, but the addition of activated charcoal had positive effect on embryogenesis in all materials. The improvement of the embryoid yield of 'X' from 18 to 34 which increased 88.89% was significant. After addition of activated charcoal, the time for appearance of the embryoid was reduced. The number of cotylednary embryos and the proportion of heart and torpedo embryoid were effectively increased.The addition of 0.2mg/L 6-BA to the microspore media in material'b' promoted the embryogenesis significantly from 18 to 34 per 30 buds. The appropriate content was 0.2mg/L. Too much 6-BA in the media had inhibition to the production of microspore embryos in this experiment. The addition of NAA to the microspore media had negative effect on embryogenesis. 3. The effect of different media on plantlet regeneration...