VEGETOS: Um Jornal Internacional de Pesquisa Vegetal

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

S Adam and S D S Murthy

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.