烟草愈伤组织继代培养与分化期间核酸代谢的比较研究

A COMPARATIVE STUDY ON THE METABOLISM OF NUCLEIC ACIDS DURING THE SUBCULTURE AND DIFFERENTIATION OF TOBACCO CALLUS

柳叶烟草愈伤组织在分化和芽原基形成期间,DNA 和RNA 含量均高于继代培养物;在芽原基形成后和幼芽生长期间(12天以后),DNA和RNA 含量持续上升,而同期继代培养物巳进入生长静止期,DNA 和RNA 含量基本不变或略有下降。根据RNA 电泳结果还进一步分析了两种愈伤组织培养物各RNA 组分变化与总RNA 含量变化的关系。分化培养物在芽原基形成时有明显升高的RNase 活性峰和持续上升的RNA 合成速率;而此时期继代培养物的RNase 活性及RNA 合成能力均较低;分化愈伤组织的DNA 合成速率在幼芽生长期间仍维持上升趋势,且显著高于同期继代愈伤组织的合成速率。这些结果表明,烟草愈伤组织分化培养物比继代培养物有更旺盛的核酸代谢能力。

Changes in the contents of DNA andRNA,RNA species,the synthesis rates ofDNA and RNA,and the activity of DNaseand RNase were investigated in the callusof tobacco(Nicotiana tabacum L.cv.Wi-llow Leaf)during subculture and differen-tiation.The contents of DNA and RNAwere higher in differentiating callus thanthat in subcultured callus.After day 12,the contents of DNA and RNA in differen-tiating callus rose continously while thecontents of DNA and RNA in subculturedcallus remained constant.Changes in RNAspecies and its relationship to total RNAlevel were also analyzed.At the stage of shoot primordium for-mation in differentiating callus,the activi-ty of RNase increased markedly and thesynthesis rate of RNA increased continous-ly;while the RNase activity and the syn-thesis rate of RNA in subcultured calluswere much lower during the same period.During the period of shoot growth,thesynthcsis rate of DNA in differentiatingcallus was elevated compared to that in sub-cultured callus.The results above suggested that themetabolism of nucleic acids in differentia-ting callus was more active than that insubcultured callus.