Study On Cold Resistance Properties And Tissue Cuiture Of Purple Sweet Potato

Large amount of anthocyanins consists in the tuber of purple sweet potato. It has great potential application in food, pharmaceuticals and chemical industry, to name a few. Purple sweet potato is one of variations of sweet potato which originated from tropical regions and has weak resistance to the low temperature. The planting expansion of purple sweet potato is then limited in north China. Cold resistance properties and the tissue cultural system of a cultivar of purple sweet potato, Zhengjiang No.1(psp-zz1), was studied in this research. This research will lay the foundation for further development in cold resistance breeding and realizing industrial seedling raising. The main results are as follows:1. Seedling leaves of psp-zzl were put in the chamber with temperature of15℃and5℃for12h, and changes of its morphology and physiology were studied. Under low temperature stress, compare with control, the leaves wilted obviously after cultured under5℃. The content of soluble sugar, soluble protein, free proline and malon dialdehyde in PSP-zzl leaves increased. The activity of SOD and CAT was increased. The correlation analysis indicated that the content of soluble sugar and protein could be used to measure cold resistance of PSP-zzl.2. The effect of different kinds and concentrations of plant hormones on psp-zzl leaves and petiole callus induction had been studied. The suitable concentration of2,4-D on induction of embryo callus from petioles and leaves was between0.05mg/L and0.1mg/L. The suitable induction medium for density type callus was0.2mg/L NAA+1.0mg/L6-BA. The suitable medium for loose callus were0.2mg/L2,4-D+0.2mg/L6-BA and1.0mg/L2,4-d+1.0mg/L ZT.3. NAA was suitable for root differentiation of callus.6-BA or KT would reduce the root differentiation, and the higher the concentration of6-BA or KT was used, the more obvious inhibition effects of root were observed. The reductive effect of6-BA was more obvious than that of KT. Full leaves with petiole cultured in medium added NAA, obtained the highest plant regeneration rate60%.The most suitable medium for plantlet regeneration is that the MS medium containing0.2mg/L of NAA. All of the regenerated plantlets can survive while they were planted in pure sterilized vermiculite.