Studies On In Vitro Culture Of Allium Chinense

Chinese jiaotou (Allium chinensis G. Don) has been cultivated vegetatively because of sterility, low propagation rate, and a laborious, time-consuming procedure and, as a result, viral infection constitutes a very serious problem in its cultivation. Tissue culture technique provides a useful tool for improving the efficiency of propagation and eliminating viruses from infected plantlets and for producing virus-free Chinese jiaotou seedlings, which improves traditional Chinese jiaotou breeding programs and produces cultivars with higher yields, higher tolerance/resistance to viral diseases. Therefore, we intended to evaluate the effects of different explants and growth regulators on callus induction and plant regeneration in this plant.The most important factors affecting plant regeneration are the explant type, the physiological condition of the explant and the growth regulator combination used in the culture medium, In this experiment, the explant such as basal plate, root, leaf and flower were used, the growth regulator 6-BA and 2,4-D and their combinations were tested on the callus induction and shoot regeneration. The results indicated that basal plate was suitable explant for in vitro callus induction and regeneration. The B₅ medium supplemented with 0.1 mg/L 6-BA and 1.0 mg/L 2,4-D proved to be optimum medium for callus induction, and the best callus proliferation was observed when cultured on B₅ medium supplemented with 1.5 mg/L 2,4-D. The highest number of adventitious shoots was achieved on B₅ medium supplemented with 0.1 mg/L 6-BA and 1.0 mg/L NAA.The highest frequency of callus induction was observed on medium containing 1.0 mg/L 2,4-D. 6-BA could promote the frequency of callus induction and 0.1 mg/L 6-BA was found to be most suitable concentration for callus induction. High concentration of 2,4-D was not only effective on callus induction but also favored the maintaince of proliferation and differentiation of cullus producd. Higher NAA concentration resulted in the higher frequency of shoot differentiation from callus.Effect of different physiological age, induced time and plant growth regulators on in vitro differentiation and regeneration of flower organ of Allium chinensis were investigated in this experiment. Results from this study demonstrated that only those buds of small and medium size could differentiate. The frequency of adventitious shoot production was higher when the segments of ovaries explants cultured for 15 d on induction medium. The best adventious shoot induction and differentitation (56.32%) occurred on ovary segments initially cultured on B₅ medium with 2.0 mg/L 6-BA, 2.0 mg/L 2,4-D and 50 g /L sucrose for 2 weeks, then subcultured to B₅ medium with 0.1 mg/L ZT, 2.0 mg/L NAA and 50 g /L sucrose for 3 weeks. The concentration and combination of auxin (NAA, 2,4-D) and cytokinin (6-BA, ZT) have a considerable effect on adventious shoots induction and regeneration.