Abstract:

【Objective】 The study was performed to explore glyphosate and post-drought rewatering on protective enzyme activities and membrane lipid peroxidation in leaves of glyphoste-resistant soybean seedlings (RR1). 【Method】 Through pot experiment, water stress and glyphosate treatments were conducted at three-trifoliolate leaf stage. Superoxide dismutase (SOD), peroxidase (POD), catalase (CAT) activities, and malondialdehyde (MDA) content and relative conductivity (EL) of RR1 were analyzed. 【Result】 In normal water condition, glyphosate increased SOD, POD, and CAT activities, MDA content, and EL of RR1, and which increased with increasing of glyphosate dosage and prolonged time in the first 5 days after glyphosate treatment. Seventeen days later, these indicators declined to some extent. In drought condition, SOD, POD, and CAT activities of RR1 treated with higher glyphosate dosages increased first and then reduced, and that treated with lower glyphosate dosages increased with prolonged stress time. However, MDA content and EL of RR1 treated with each glyphosate dosage increased to the largest on the 5th day, and declined 12 days after rewatering. The SOD, POD, and CAT activities, MDA content and EL of RR1 treated with glyphosate in drought condition were higher than that in normal water condition. 【Conclusion】 In normal water condition, the injury of RR1 caused by glyphosate could be eased through a period of growth and development. The reasons which drought stress aggravated the injury of RR1 caused by glyphosate were metabolic imbalance of reactive oxygen species, changes in protective enzyme activities and increased in the plasma membrane peroxidation. Rewatering after short-term drought stress could enhance the drought–resistant or stress-adaptive ability of the cell membrane.

Key words: drought, glyphosate, glyphosate-resistant soybean, protective enzymes, membrane lipid peroxidation