烟草愈伤组织继代培养和分化期间蛋白质代谢的比较研究

A COMPARATIVE STUDY ON PROTEIN METABOLISM DURI NG SUBCULTURE AND DIFFERENTIATION OF TOBACCO CALLUS

柳叶烟草(Nicotiana tabacum L.)愈伤组织在分化和芽原基形成期间,与继代增殖培养物比较,蛋白质含量与蛋白水解酶活性均缓慢上升;组分Ⅱ(水溶性蛋白与酶蛋白)蛋白质和核糖体组蛋白的合成速率都明显高于继代培养物;分化组织中总核糖体水平,特别是执行蛋白质合成功能的多聚核糖体的构建也都高于继代培养物。显然,分化培养愈伤组织较继代培养物有更高的蛋白质合成作用;而且组织分化和芽原基形成所需合成的新蛋白组分是与继代增殖生长的不同。继代培养后期,蛋白水解酶活性迅速升高,多聚核糖体相对量与蛋白质合成速率均明显下降,蛋白质含量急剧降低,表现出继代培养物开始衰老的代谢特征。此时期的分化培养组织,随着芽原基的继续生长,虽然蛋白质合成速率、多聚核糖体水平与蛋白质含量较前期有所降低,但都明显高于同时期的继代培养愈伤组织。

Comparative study on the subcultured callus of tobacco(Nicotiana tabacum L.cv.Willow leaf)has revealed that protein contents and protease activities slowly decreased in the callus during differentiation and bud formation.The synthetic rates of fraction Ⅱ protein(water so- luble protein and enzymes)and ribosomal hist one,the levels of total ribosomes,especially the levels of polyribosomes which function the protein synthesis,were higher in the differentia- ring callus than those in the subcultured callus.This indicates that protein synthesis in diffe- rentiating callus is greater than that in non-differentiating callus,and that the protein pattern synthesized in differentiating callus may differ from that in non-differentiating callus.Du- ring the late period of culture,the protease activities in subcultured callus rapidly increased, and the levels of polyribosomes,protein synthetic rates and protein contents apparently declined, which may be the result of metabolic changes in callus senescence.Meanwhile in the differen- tiating callus the protein contents,protein synthesis rates and polyribosome levels although so- mewhat declined accempanying the growth of formed bud,were still much higher than those in the subcultured callus.