Figure 4: In situ detection of ROS and measurement of GSH contents.

(a) A ‘Marble Queen’ leaf with distinct green and white sectors before (left) and after treatment with 6 mM NBT (right). The formation of insoluble dark blue diformazan came from the reduction of NBT by the presence of superoxide. (b) Total GSH was measured and compared between VMG and VMW. Data represents an average from three independent pairs of sectors ± SD. The arrow represents an increase (↑) in fold (x). **P < 0.01.