Abstract
We have previously reported that glutathione is associated with regulation of photosynthesis in Arabidopsis thaliana. Here we show that exogenous GSH and GSSG can increase leaf CO2 fixation in A. thaliana in a manner different from each other. Wild-type plants (Columbia) were supplemented with GSH or GSSG by weekly subirrigation until five weeks passed after sowing. Compared to no supplementation, GSSG and GSH increased seed and biomass yield. GSSG and GSH also promoted leaf-area-based CO2 fixation with increasing nitrogen and chlorophyll contents in five-day-old plants. GSH raised Chl a/b ratio, whereas GSSG did not cause any significant change in Chl a/b ratio. GSH-supplemented plants had about 2-fold more Rubisco content than that of non-supplemented plants, while GSSG-supplemented plants had 1.3-fold more Rubisco than the control plants. Taken together, these indicate that both GSH and GSSG have an increasing effect on photosynthesis, but that the mechanisms are different from each other.
