Study On Construction Regeneration System Of Pumpkin Tissue Culture

Plant tissue culture technology has been used of melon, watermelon, cucumber and so on. There are not very many studies in pumpkin culture in vitro yet. Thus, study of regeneration system in pumpkin is of a great theoretical significance and practical value in resource conservation, somatic breeding, genetic transformation and bioreactor.Five materials of pumpkin have been used in this study to compare the seed storage time, sterile time and mineral element effect in the response to tissue culture. The plant growth substances, genotype, explant type cotyledon dissection and inoculation methods have been also investigated, which effect the callus induction, adventitious bud differentiation and adventitious root differentiation. Thus, we have established pumpkin regeneration system in vitro.The best regeneration rate has been achieved in short storage time of the seeds, high quality seeds, cutting the cotyledon into half longitudinally of 4-5 day old seedlings, placing the middle leaf vein in the medium.The best genotypes were Luli and Yixianghongli to induce the adventitious bud among pumpkin species tested. The best medium composition for adventitious bud culture was MS+6-BA 3.0 mg/L+NAA 0.1mg/L with adventitious bud differentiation ratio of 37.5%, producing average 2.2 buds for Yixianghongli. Whereas best medium composition for Luli was MS+6-BA 3.0 mg/L+NAA 0.1mg/L for 12 days, and transferred into MS+6-BA 2.0 mg/L+NAA 0.5mg/L with the adventitious bud ratio of 52%, average 3.7 buds.Only cotyledons had the ability to generate adventitious bud in pumpkin and"polarity phenomenon"was occurred during the cotyledon culture. The adventitious buds were localized in the cutting parts of leaf base. After adventitious bud elongating, they were transferred to MS+1.0 mg/NAA media, the adventitious roots and plantlets were then generated.In this study the regeneration system was established with the adventitious buds without auxiliary bud in pumpkin.