Changes in protein profile during sulphur-dioxide fumigation of Vigna unguiculata L.

摘要

Sulphur-dioxide fumigation affected CO_2 fixation process, so that free CO_2 could increase in the cells which was not fixed through photosynthesis. Also, the photosynthesis damage was not persistent due to the dissolved SO_2 and its subsequent reactions. Intact chloroplasts isolated from fumigated leaves showed that only PSII electron transport was inhibited and PSI was not affected. Marked changes in the chloroplasts protein profile were observed and gradual denaturation of 55, 33, 23 and 18 kDa polypeptides had occurred due to SO_2 fumigation. Sulphite and pH of the cells made detachment of polypeptides from the oxidizing side of PSII, thereby affecting the PSII electron transport and photosynthesis process of plant.