Abstract:
The ameliorative effect of salicylic acid (SA: 0.5 mM) under Cu stress (5 mg L–1) in sunflower (Helianthus annuus L.) was studied. Excess Cu reduced the fresh and dry weights of different organs (roots, stems and leaves) and photosynthetic pigments (chlorophyll a, b and carotenoids) in four-week-old plants. There was a considerable increase in Chl a/b ratio and lipid peroxidation in both the roots and leaves of plants under excess Cu. Soluble sugars and free amino acids in the roots also decreased under Cu stress. However, soluble sugars in the leaves, free amino acids in the stems and leaves and proline content in all the plant organs increased in response to Cu toxicity. Salicylic Acid (SA) significantly reduced the chlorophyll a/b ratio and the level of lipid peroxidation in Cu-stressed plants. Under excess Cu, a higher accumulation of soluble sugars, soluble proteins and free amino acids including proline occurred in plants treated with SA. Exogenous application of SA appeared to induce an adaptive response to Cu toxicity including the accumulation of organic solutes leading to protective reactions to the photosynthetic pigments and a reduction in membranes damage in sunflower.
M.A. El-tayeb, A.E. El-Enany and N.l. Ahmed, 2006. Salicylic Acid-induced Adaptive Response to Copper Stress in Sunflower (Helianthus annuus L.). International Journal of Botany, 2: 372-379.
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