The effect of risk elements in soil to nitric oxide metabolism in tobacco plants.

We studied changes of endogenous nitric oxide content (NO) and of reactive nitrogen species metabolism in transgenic tobacco with prolonged life span (SAG) and in wild tobacco (WT) cultivated in the control and in the polluted soil. There was no difference in the metal accumulation between WT and SAG plants however SAG ones showed better ability to cope with risk elements, as they retained higher membrane stability index and chlorophyll content together with better photochemical efficiency and lower deepoxidation status. Risk elements induced higher NO production in the youngest leaves of both plant types. Low and middle leaves of both WT and SAG plants showed similar activities of nitrate reductase and nitrosoglutathione reductase. Increase of nitrotyrosine content in leaf soluble proteins suggests that risk elements induced nitrosative stress in both plant types.