1-MCP Effects on Antioxidant Activity and Gene Expression of ACC-Synthase and ACC-Oxidase In Cotton Flowers

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. The 1-Methylcyclopropene (1-MCP) is a plant growth regulator that works by decreasing or delaying the effect of ethylene which normally acts as an endogenous stress and senescence phytohormone.  1-MCP has been shown to overcome environmental stress problems and achieve higher and more stable yields. The objectives were to evaluate the effect of 1-MCP application on cotton flowers: on gene expression involved in ethylene synthesis and on the responses of oxidative stress physiology. The treatments consisted of untreated and 1-MCP treated (10 g ai ha^-1) flowers collected 1 day after treatment application. The results showed that application of 1-MCP significantly reduced the expression of ACC oxidase;  but did not have an effect on ACC synthase. Measurements of oxidative stress indicated that 1-MCP treated flowers had a significant reduction on GR and SOD levels. No effect of 1-MCP on membrane degradation  was observed.