Studies On The Techniques Of Isolated Microspore Culture In Chinese Cabbage And Primary Application

Fifty genotypes were used for isolated microspore culture in Chinese Cabbage (Brassica campestris ssp.pekinensis Lour.) .The studies included affecting factors to microspore embryogenesis and microspore plants regeneration, the methods of increasing microspore plants regeneration rate , the ploidy identification of microspore plants and the selection of parent homozygous lines. The main results were as follows:1. In microspore embryogenesis capacity, there was very great difference in each genotype. The embryoid inducement frequency was 76.6 %in the middle-and-late-mature varierites and 80.0% in the premature ones.And the highest embryoid yield was 100 and 78 per bud.2. The cytological observation showed that most of the microspores in the late uninucleate stage were suitable for cultivating when the bud size was 2.5~ 3.0mm .The temperature from three days before the bud plucking day was a key factor and 14~24℃ was most suitable to induce microspore embryogenesis.The buds in full florescence and the donor plant with good nutritional status were also suitable to induce microspore embryogenesis and plant regeneration.3. Medium NLN was the only one to induce microspore embryogenesis.And medium NLN supplemented with appropriate amount of hormones and active charcoal had a good effect on embryogenesis and plant regeneration.The optimal concentration of sugar was 13% which could providing enough energy source and osmotic pressure.The heat-shock pretreation on the microspore at 32℃ was necessary for the embryogenesis.while low-temperature pretreation on the buds did no effect on the embryogenesis.4. The plant regeneration frequency was closely related to embryo...