Study On Inducement For Salt-tolerant Somaclonal Line And Morphological Observation Of Tetraploid Variant From Regenerated Melon

Regeneration systems for two melon varieties, Queen and K7-3, were established by tissue culture. The regenerated plants were transplanted in the field after hardening. The morphological traits observation of tetraploid variants from the regenerated melon and inducement of salt-tolerant somaclonal line were studied, the main results were as following:Adventitious shoot were induced from the basal cotyledon after seed germination in 2～4 days, the apical cotyledon was inserted in MS medium containing 1mg/L BA. The highest regeneration frequency was 96% and 88% in K7-3 and Queen respectively. MS medium containing 0.5mg/LIBA for rooting was the best.The technological process for hardening and transplanting of the seedlings were summarized. The percentage of survival transplants were up to 100% in high pressure sterilized sawdust medium.There are a number of tetraploid variants in the regenerated plants by tissue culture. By mesns of inducing roots prior to shooting from callus, the percentage of tetraploid plants was increased from 28% to 66.67% due to culture time was prolonged for 55 days. The morphological traits of stem, leaf, stoma, flower, pollen, seed in shape and size, and fruits between the diploid and tetraploid were compared, the tetraploid plants in morphological characters exhibited significant difference from the diploid.LD50 for callus is 10g/L NaCl, and duration of culture is another important factor. Once the culture duration was prolonged, the percentage of survival cotyledon explants would be decreased in the same NaCl concentration. The calli were cultured on MS medium containing higher NaCl concentration for a period of time, then transferred to the medium containing lower NaCl concentration, the percentage of survival calli increased.