Effect of zinc stress and GSH inhibitor on relative growth of wild-type and glyoxalase transgenic tobacco plants (GI, glyoxalase I; GII, glyoxalase II; and GI + II, double transgenics). A, Representative image of seedlings showing relative growth of wild-type (WT) and transgenic plants under control conditions (C; 0.5× Murashige and Skoog) or in the presence of 100 μm GSH inhibitor BSO or both 5 mm ZnCl2 + 100 μm BSO for 25 d. B and C, Histograms showing levels of GSH (B) and PCs (C) in seedlings of wild-type and glyoxalase transgenics exposed to 5 mm ZnCl2, 100 μm BSO, or both 5 mm ZnCl2 + 100 μm BSO for 24 h. Values are the mean of three independent estimations ±sd. Note the higher content of GSH and PCs in double transgenics.