盐胁迫下烟草愈伤组织内源活性氧及乙烯的产生与交替途径发生、运行的关系

RELATIONSHIP BETWEEN ENDOGENOUS ACTIVE OXYGEN SPECIES,ETHYLENE AND THE DEVELOPMENT AND OPERATION OF THE ALTERNATIVE PATHWAY IN TOBACCO CALLUS UNDER SALT STRESS

本文初次报告了烟草愈伤组织在不同盐浓度胁迫下交替途径与细胞色素途径的动态变化,同时检测了内源乙烯产生速率和活性氧(O_2、H_2O_2和·OH)的含量及其相关酶(SOD和CAT)活性的变化。结果表明,交替途径实际运行量(ρV_(alt))先逐渐上升,于0.75%盐浓度左右时达到极大值,但交替途径容量(V_(alt))与ρV_(alt)并不同步,且细胞色素途径活性(ρ'V_(cyt))与ρV_(alt)变化趋势相反。与此同时,愈伤组织体内H_2O_2和O_2迅速积累,分别在0.5%和0.75%左右达到极大值,·OH则一直呈上升趋势。而内源乙烯产生速率先急剧上升,在0.5%盐浓度左右时达到极大值后下降。将上述变化与各呼吸参数变化相比较发现,H_2O_2含量和乙烯产生速率与V_(alt)变化曲线同步,而O_2与ρV_(alt)变化曲线一致,但·OH含量与V_(alt)变化曲线呈负相关。据此我们推测抗氰交替途径的发生、运行可能与活性氧的积累以及乙烯的产生密切相关,并讨论了交替途径运行的一些可能的生理作用。

This paper reported firstly the dynamic changes of the alternative pathway and the cy-tochrome pathway in tobacco callus under different concentration of salt. The production rate of endogenous ethylene, the contents of active oxygen species (O2, ·OH and H2O2) and the activities of related enzyme (SOD and CAT) were also investigated simultaneously. The results indicated that the actual operation of the alternative pathway (pValt) increased gradually and reached the maxima at 0. 75 % salt concentration, then declined, while the capacity of the alternative pathway (Valt) didn't exhibit the same change pattern with pValt and the cytochrome pathway (p'Vcyt) changed contrary to pValt. At the same time, H2O2 and O2 accumulated rapidly and reached their peak value at about 0. 5% and0. 75% salt concentration respectively, while the content of · OH increased consistently. The production rate of endogenous ethylene increased rapidly and reached its maxima at about 0. 5% salt concentration. These data demonstrated that changes of Valt in tobacco callus were associated with a parallel production of H2O2 and endogenous ethylene and a opposite production of · OH, while pValt changed parally with the production of O2. On the basis of above results, it was deduced that the changes of the development and operation of the alternative pathway in tobacco callus under salt stress might be correlated with the production of endogenous ethylene and the active oxygen species. The possible participation of the alternative pathway in response to salt stress was also discussed.