Dr. Gossett et al., ANTIOXIDANT RESPONSE TO NACL STRESS IN SALT-TOLERANT AND SALT-SENSITIVE CULTIVARS OF COTTON, Crop science, 34(3), 1994, pp. 706-714
The mechanism(s) imparting salt tolerance to plants remains unresolved
. Although cotton (Gossypium hirsutum L.) is classified as a salt-tole
rant plant, variation in salt tolerance has been observed among differ
ent cultivars. The purpose of this study was to determine if more salt
-tolerant cultivars contain higher constitutive or inducible levels of
antioxidants than more salt-sensitive cultivars. Greenhouse-grown sal
t-tolerant (cv. Acala 1517-88 and Acala 1517-SR2) and salt-sensitive (
cv. Deltapine 50 and Stoneville 825) cotton plants treated with either
0 or 150 mM NaCl were analyzed for differences in growth and antioxid
ant capacities. The 150 mM NaCl treatment resulted in more than 40% re
duction in growth of Deltapine 50 and Stoneville 825 and less than 30%
reduction in the Acala cultivars. The more salt-tolerant cultivars ha
d higher constitutive levels of catalase (121-215%) and alpha-tocopher
ol (312-420%). The salt treatment resulted in a 38 to 72% increase in
peroxidase activity and a 55 to 101% increase in glutathione reductase
activity in the Acala cultivars while the activities of these enzymes
remained constant or decreased in the more sensitive cultivars. The A
cala cultivars also exhibited a lower oxidized/reduced ascorbic acid r
atio and a higher reduced/oxidized glutathione ratio than the more sen
sitive cultivars when grown at 150 mM NaCl. When subjected to a one-ti
me salt treatment, lipid peroxidation in Deltapine 50 increased 51% ov
er Acala 1517-88. These data indicate that protection from oxidative d
amage by higher levels of antioxidants and a more active ascorbate-glu
tathione cycle may be involved in tbe development of salt tolerance in
cotton.