Influence of drought stress on growth, ion accumulation and antioxidative enzymes in okra genotypes
2012
Kusvuran, S. (Cankiri Karatekin Univ. (Turkey). Kizilirmak Vocational High School)
The aim of this study was to investigate the effects of drought stress on plant growth, relative water content (RWC), ion concentration and activities of antioxidant enzymes, glutathione reductase (GR), and ascorbate peroxidase (APX) in 8 okra genotypes. Seeds were germinated in a mixture of peat: perlite of 2:1 ratio. After 16 days of sowing, seedlings were transferred to plastic pots containing mixture of peat: perlite of 2:1 ratio. Drought stress was achieved by decreasing the irrigation water gradually over 4 days (100%, 75%, 50% & 25%). There were considerable differences among the okra genotypes in their physiological responses to drought. Significant differences in response to drought were found to be closely related to differences in the potassium (K) and calcium (Ca) contents and the activities of antioxidant enzymes. Okra genotypes Okr-6, Okr-67, and Okr-105 showed higher antioxidant activity and higher K and Ca concentrations in the shoots and roots; therefore, were better able to perform better under drought stress. Whereas, genotypes Okr-47 and Okr-112 showed lower antioxidant activity and lower K and Ca concentrations and didn't perform well under drought. In conclusion, drought resistant genotypes exhibit a better protection mechanism against oxidative damage by maintaining a higher inherited and induced activity of antioxidant enzymes than the sensitive genotypes.
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