Research On Influence Factors Of In Vitro Regeneration Of Cucumber

Cucumber(Cucumis sativus L.) is a kind of important vegetable crops and widely cultivated in the world. With the development of molecular biology techniques, genetic transformation technique has become an important improvement means of many crop varieties. But it is difficult to establish the tissue culture of cucumber with strong gene specific, high frequency regeneration, and it also limits the application of these technologies in cucumber breeding. Various factors which influence the regeneration of cucumber, such as genotype, hormones, explant, ages of explant and rooting are researched. In this study, we establish a complete efficient regeneration system of cucumber cotyledons petiole, and the main results are as follows:1. The genotype is one of the main factors affecting the regeneration ability of cucumber in vitro, the difference between the regeneration ability of different genotypes of cucumber varieties of great. Three varieties that used to establish cucumber cotyledon petiole regeneration system (Jinlv No.3, Lvyuan No.8 and Xinsihao), the regeneration frequency of Jinlv No.3 and Xinsihao are high in the culture medium MS+ 0.5 mg.L-16-BA+ 0.6 mg.L-1 IAA, and the regeneration frequency are 75% and 77%, the number of explants budding are 5.6 and 5.2. While regeneration frequency and the number of explants budding of Lvyuan No.8 are 30% and 3.3.2. Plant hormones are necessary for in vitro regeneration of cucumber.6-BA is one of the most plant hormone for in vitro regeneration of cucumber. For the differentiation of cucumber cotyledon petiole explants,6-BA is the main factor of adventitious bud and IAA can improve the indefinite bud number. Regeneration frequency and the number of explants budding of three varieties are all reached the highest in the culture medium MS+ 0.5 mg.L-16-BA+ 0.6 mg.L-1 IAA. So the best bud induction medium is MS+0.5 mg.L-16-BA+ 0.6 mg.L-1 IAA.3. Regeneration of different explants of cucumber is of great differences, in the best bud induction medium, seedling age of Jinlv No.3, Lvyuan No.8 and Xinsihao are 5 days, regeneration frequency of cotyledon petiole are 75%,30% and 70%, while no buds generate in cotyledons with no petiole and hypocotyl. In this study, cotyledons petiole is the optimal explant to establish regeneration system.4. Age of seedling is an important factor affecting the regeneration frequency of cucumber. In the 3-7d seedling of cotyledons petiole, regeneration frequency and number of explants budding of Jinlv No.3 reach the highest at the age of 5 days,75% and 5.6 respectively. While the regeneration frequency and number of explants budding of Lvyuan No.8 and Xinsihao reach the highest at the age of 4 days, the regeneration frequency are 77% and 25%, and the number of explants budding are 5.2 and 4.3. The best age of seedling of Jinlv No.3 is 5 days; Lvyuan No.8 and Xinsihao are 4 days.5. In conclusion, MS+0.5mg.L-16-BA+0.6mg.L-1 IAA were used as bud induction medium, the age of Jinlv No.3 is 5 days, while the age of Lvyuan No.8 and Xinsihao are 4 days. Cotyledons with petiole were used as the explants, using the direct way of organ, in a relatively short period of time to obtain a certain amount of regenerated plantlets. Efficient regeneration systems of three genotypes were established, which lay the foundation for the development of genetic transformation of cucumber.