Vitamin or Salicylic acid treatments versus the adverse effects of copper stress on photosynthesis and some related activities of wheat seedlings.

Abstract

The addition of 100 ppm of any of the vitamins; ascorbic acid (AsA) or thiamin (B1) as well salicylic acid (SA) to the hydroponic growth solution for one day of young wheat plants exerted protective effects against copper stress. Excessively copper supply (for 3 days) considerably retarded the rates of photosynthesis and some of the related activities of wheat seedlings; a serious effect was exhibited when copper was applied at relatively high levels. These negative alterations in net photosynthesis were generally associated with a reciprocal response in dark respiration. On the other side AsA, B1 or SA treatments were generally effective in alleviating partially or completely the inhibitory effects of copper stress on growth and net photosynthesis of the test seedlings. However, these treatments were associated with favorable effects on the biosynthesis of photosynthetic pigments. As regards the dark respiration, while in vitamin treated plants, it was mostly retarded, whatever the level of copper used and the type of vitamin applied, in salicylic acid treated plants, respiration was progressively stimulated.