The Study Of Exogenous Hormone Effect On Endogenous Hormone In The Callus Tissue Culture Of Nitraria Tangutorum Bobr.

Nitraria tangutorum Bobr. is a specific species with ecological function and economic value in the northwest desertized areas of China. On the basis of the optimized condition of callus induction, the endogenous hormone changes of stems or callus cultivated on no hormone MS medium and the exogenous hormone effect on endogenous hormone in callus were studied with the high performance liquid chromatography technique. From the above study, the interaction relation between endogenous and exogenous hormone could be known and the appropriate proportion of hormone could be resolved which could help to achieve the callus regeneration of N. tangutorum Bobr. . The important results were as follows :1. The optimized condition was selected to induce callus in N. tangutorum Bobr..The suiTab. condition was that 0.50 mg/L 2,4-D was added on MS basal medium and with the stems as explants. Under this condition, the induction ratio of callus was 94%, the relative biomass was 0.59 and the callus induced showed the easily regeneration characteristics.2. Endogenous hormone concentration of terminal buds grew at different environment were determined. In the natural terminal buds of N. tangutorum Bobr., the contents of auxin, cytokinin, gibberellin and abscisic acid were 149.02 ng/g, 139.89ng/g, 295.61ng/g and 250.45ng/g respectively, while the ratio of Zt/IAA was 0.94, GA₃/ABA was 1.18, and IAA/ABA and Zt/GA₃ were 0.60 and 0.47 Similarly, in the axenic terminal buds of N. tangutorum Bobr., the content of auxin was 165.78 ng/g and that of cytokinin, gibberellin and absicsic acid were 143.14 ng/g, 307.39 ng/g and 240.81 ng/g. Except for absicsic acid ,the other hormone concentration of axenic terminal buds were higher than that of the natural ones. The ratio of Zt/IAA , GA₃/ABA ,IAA/ABA and Zt/GA₃ were 0.86 , 1.28 ,0.69 and 0.47 respectively.3. When the stems with axillary buds were cultivated on no hormone MS medium, the apical dominance of terminal buds gradually disappeared and the axillary buds gradually grew up. In the process, the content of gibberellin and absicsic acid changed with not significant, while the content of auxin gradually increased and that of cytokinin gradually decreased. And then, the endogenous hormone tended to be steady at 15 days after cultivated and the concentration and ratio of endogenous hormone were almost equal to terminal buds, which suggested that the change of the stems with axillary buds intoterminal buds was actually the ebb and flow process of auxin and cytokinin.4. In the callus tissue culture of N. tangutorum Bobr., the exogenous hormone and the endogenous hormone affect each other strongly. When different concentration of exogenous hormone were added, the synthesis of endogenous hormone in the callus of N. tangutorum Bobr. was improved and the content of it was increased and the ratio between endogenous hormones was changed. But the influence of different exogenous hormone on the concentratin of endogenous hormone was different. Either the content of exogenous hormone or the ratio of different exogenous hormone was departed from that of terminal buds seriously.5. The endogenous hormone concentration of callus were compared with the natural or axenic terminal buds in N. tangutorum Bobr. It was found that when adding 1.00mg/L NAA and 1.00mg/L6-BA or 1.00mg/L NAA and 1.00mg/L Kt the concentration and the ratio of endogenous hormone in callus were close to that of natural or axenic terminal buds in N. tangutorum Bobr. It suggested that the two combination of exogenous hormone and their proporation would be fit for the callus regeneration of N. tangutorum Bobr.