烟草叶片脱分化阶段性及培养物呼吸代谢类型的研究

研究发现烟草叶片外植体脱分化是分阶段完成的：在诱导期（２ｄ内）产生的愈伤细胞须通过发育期进入成熟期（８ｄ后）才能脱去叶片外植体固有的构型方式的影响．否则，未通过发育期的培养体，在芽分化培养基中只能形成一种倒生的畸形叶状体．在关键的发育期出现了由水杨基氧肟酸（ＳＨＡＭ）敏感途径及Ｎａ３ＰＯ４敏感途径加强而构成的类似呼吸跃变现象，而呼吸商却出现低于１．０的低谷，同时三羧酸（ＴＣＡ）循环的偏呼吸商（ＰａｒｔｉａｌＲｅｓｐｉｒａｔｏｒｙＱｕｏｔｉｅｎｔ）也小于１．０．在芽分化过程中也发现类似的代谢类型变化．讨论了这种代谢类型变化的生理意义．

STUDIES ON THE PHASES OF TOBACCO LEAF DEDIFFERENTIATION AND RESPIRATORY METABOLISM PATTERNS OF IN VITRO CULTURERS

The processes of tobacco (Nicotiana tobaccum) callus initiation,development and redifferentiation,and the associated changes of respiratory metabolism pattern were studied. Dedifferentiation was found to be completed by phases. The callus cells formed during the initiation phase (within 2 days) could not get rid of the influence of the programmed pattern of formation from the mother leaf explants,until they had passed through the development phase and entered the maturation phase (after day 8).Otherwise,the callus cells produced only gravitropic leaf-like bodies on bud differentiating medium. At the crucial development phase,a climacteric-like respiration peak composed of the enhanced SHAM sensitive and Na 3PO 4 sensitive pathways took place,while RQ fell to a low value of less than 1 0. At the same time,TCA cycle contribution to the rate of CO 2 release decreased drastically,causing its partial respiratory quotient (PRQ) also to go down to less than 1 0. During bud primordium formation on differentiation medium,a similar respiratory pattern change was observed. The physiological roles of the metabolism changes were discussed.