Effects of lead (Pb, 150 and 300 µM) alone or in combination with methyl jasmonate (MJ, 0.5 and 1 μM) on the activity of glyoxalase I (Gly I, A), glyoxalase II (Gly II, B), and the phytochelatins content in root (C) and leaf (D) in rice. Values (means ± SD, n = 5) followed by the same letter are not significantly different (P < 0.05; LSD test)