Tissue Culture And Genetic Biochemical Analysis Of Chinese Onion

A regeneration system of tissue culture in vitro using seeds as explant was established on Chinese Onion and the factors inducing vitreous shoots and the esterase isoenzyme and the soluble protein between normal shoots and vitreous shoots and the chromosome variation were learned in this paper. The main results are summarized as follows:1 Using sterilized seeds as explant,MS basal medium supplemented with 2,4-D2.5 mg.L-1and BA 0.5 mg.L-1 was advantageous to callus induction and the frequency of callus induction was 86.95%; MS basal medium combined with BA2.0 mg.L-1 was the best for callus differentiation for three culture ages with the ratio of 63.9%ï¼›94.19ï¼…of the regenerated plants only treated on the MS basal medium could develop their roots and the surviving rate of transplanting was 83.3ï¼….The system greatly increased the efficiency of Chinese Onion tissue culture.2 Three factors of hormones,sugar and agar infecting vitreous shoots during tissue culture were studied. The number of vitreous shoots enhanced with the increase of the concentration of BA and the optimum concentration of BA was 2.0 mg.L-1 The relationship between the concentration of sugar and agar and the number of vitreous shoots was obviously negative correlation and the correlative coefficient were -0.962 and -0.990.The result manifested that the best consistency of sugar and agar were 3% and 1.2%. During the induction and subculture of test tube plants, increasing illumination could reduce occurrence of vitreous shoots too.3 The result of esterase isoenzyme of green and vitreous plants showed that there were four main bands in green shoots; The vitreous plants was a lack of the bands of Rf0.0852 and Rf0.457 but added Rf0.229 of high activity, this band was likely vitreous feature and the gene controlling esterase and the vitreous character had osculate relation. From the observation their soluble protein, the vitreous shoots included all the main protein bands and it added 4 bands of higher molecular weight which may be the characteristic bands and the proteins especially expressed facing with imbalance condition of growth; Other bands had no distinct difference, which may be the necessary proteins that maintained two development states, the construction genes were all along in vivid condition.4 Chromosome variation was found in callus and regenerated plants of Chinese onion on MS basal medium containing 2,4-D2.0 mg.L-1and BA 0.5mg.L-1.The frequency of chromosome variation of callus enhanced with the increasing of culture ages. The variable cells of callus were the most of hypodiploid and the numble of tetraploid in regenerated plants differentiated from callus of ten subculture times occupied the most. At the same time, from the RAPD result of four samples, we gained one stablely polymorpHic segment of 1200bp from the callus of ten culture ages and the regenerated plant from it. The result telled that the subcultures could lead to the change of DNA which may one important reason of the chromosome variation.