Inhibition of Photosynthetic Electron Transport Activities in Maize Seedlings by Treatment with Toxic Concentrations of Zinc

Inhibition of Photosynthetic Electron Transport Activities in Maize Seedlings by Treatment with Toxic Concentrations of Zinc

The effect of zinc at high concentration (60-180μM) has been investigated in maize seedlings in controlled environment. Zinc treatment caused inhibition in whole chain electron transport and Photosystem (PS) -II catalyzed electron transport by 48% at 120 μM concentration. Further rise to 180 μM concentration caused damage and inhibited PS-II activity. But at the same concentration, 29% loss was noted in PS-I catalyzed electron transport activity. Light intensity alterations clearly demonstrate that the inhibition was at light saturating conditions (416Wm-2) rather than the light limiting conditions (24Wm-2) which concludes that LHC-II of PS-II is the main target for zinc stress.