In the present study, Kandelia obovata (S.,
L.) Yong seedlings were exposed to As V(0, 30, 60 and 150 mg kg-1) under
different levels of sulfur (0, 0.1, 0.2 and 0.4% (w: w)) supply. A highly
significant negative correlation between arsenic concentration in leaves with sulfur
treatment (r=-0.554, P<0.01) is established. Concentration of arsenic in
roots proves much higher than that in leaves. The GSH concentrations in K.
obovata seedlings show significantly increases (rleave=0.648, rroot=0.602;
P<0.01) with increasing sulfur supply in the growth media. Arsenic induced
GSH formation in leaves of K. obovata seedlings, and clearly restrained GSH
formation in roots. Arsenic exposure significantly increased the synthesis of non-protein
thiols (NPT). Supply of sulfur at 0.1% and 0.2% promoted the content of NPT
(P<0.05), but at 0.4% sulfur there was little effect on the NPT content
(P>0.05). In conclusion, an increase in sulfur supply to plants may improve
their accumulation capacity for arsenic through enhanced tolerance caused by a
positive effect on the thiol metabolism of the plants.
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