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Pak. J. Bot., 42(1): 559-565, 2010.

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RESPONSE  OF  TWO  GENETICALLY  DIVERSE  WHEAT CULTIVARS TO SALT STRESS AT DIFFERENT GROWTH STAGES: LEAF LIPID PEROXIDATION AND PHENOLIC CONTENTS

MUHAMMAD ARSLAN ASHRAF¹, MUHAMMAD ASHRAF^12* AND QASIM ALI¹

Abstract: The effect of root zone salinity on two hexaploid bread wheat (Triticum aestivum L.) cultivars (S-24, salt-tolerant; MH-97, salt-sensitive) was appraised at different growth stages. Grains of the two cultivars were sown in Petri-plates at two salt levels (0 and 150 mM of NaCl). After 8 days of germination, the seedlings were transplanted into plastic tubs containing either 0 or 150 mM of NaCl in full strength Hoagland’s nutrient solution. Changes in growth, lipid peroxidation and phenolic contents were examined in the cultivars at different growth stages (vegetative, booting and reproductive) under salt stress. Higher MDA contents were observed in cv. MH-97 as compared to that in S-24 under saline regimes at different growth stages. Salt-induced effect in terms of lipid peroxidation was more pronounced at the booting and reproductive stages as compared with that at the vegetative stage in both cultivars, however, the accumulation of leaf total phenolics was higher at the booting stage as compared with that at the other stages. A significant variability in salt response was found among different growth stages in both cultivars. Correlations among growth and biochemical parameters showed a  significant negative correlation between growth and MDA content but a positive correlation  between growth and phenolic contents, which shows that phenolic compounds were involved in the mechanism of salt tolerance of the two cultivars by showing enhanced antioxidant activity which resulted in reduced membrane damage and hence improved growth.

¹Department of Botany, University of Agriculture, Faisalabad, Pakistan

²Second affiliation: King Saud University, Riyadh, Saudi Arabia.