The Effects of 1-Methylcyclopropene On the Physiology and Yield of Cotton

Drought and high temperature play a major role in limiting crop productivity around the world. Plants under stress conditions usually exhibit an increase in ethylene synthesis. Ethylene normally acts as trigger to the processes of plant senescence and fruit abscission. 1-methylcyclopropene (1-MCP) is a plant growth regulator that inhibits ethylene action, by delaying or decreasing the plant response to ethylene. The current field and growth room studies were designed with the objectives of investigating the effects of 1-MCP (1) on the growth and yield of cotton, (2) on the physiology of cotton plants under water-stress and well-watered conditions, and (3) on ethylene production and antioxidant levels of cotton reproductive organs under high and normal temperatures. Results indicated that 1-MCP treated plants exhibited higher maximum quantum efficiency of Photosystem II, decreased the activity of antioxidant glutathione reductase, better maintenance of cell membrane integrity, decreased ethylene synthesis of cotton reproductive organs, increased cotton boll weight, and no effect on cotton fruit abscission. Cotton yield was significantly increased by 1-MCP applied twice (at the first flower stage and two weeks later) by 228 kg/ha of lint and 320 kg/ha of seeds compared to the untreated control. Overall the application of 1-MCP to cotton was shown to decrease stress in the plant, by inhibiting the action of ethylene, which resulted improved plant response to stress and increased in yield.