Abstract:The transient characteristics of chlorophyll fluorescence induction, the activities of respiratory enzymes (malate dehydrogenase, isocitrate dehydrogenese, suecinate dehydrogenase and cytochrome C oxidase) and the activities of photorespiratory enzymes (hydroxypyruvate reductase, glycolate oxidase and catalase) in the transgenic tobacco (Nicotiana tabacum L. ), in which betaine aldehyde dehydrogenase (BADH) gene had been introduced, were determined and compared with the parent plants. The results showed that the Fy/Fo, Fv/Fm and Fd/Fs of the transgenic plant had no changes; the activities of ma]ate dehydrogenase, isocitric dehydrogenase and succinic dehydrogenase in tricarboxylic acid cycle had a slight increase, and the activity of eytochrome C oxidase in the terminal oxidative pathway had a significant increase. The activities of hydroxypyruvate reductase, glycol]ic oxidase and catalase in the photorespiratory pathway had a marked increase. The possible significance on these changes was discussed.