The effects of spraying methanol solution and drought stress on level of antioxidant enzyme activity, growth, biomass and yield of beans (Phaseolus vulgaris L.cv. COS16)

An experiment was conducted to investigate the effect of methanol solution spray treatment on growth, biomass, and functional properties of bean plant under drought stress. The experiment was set up as a fully-randomized design with three replications. The first factor was four concentration levels of spray solution (Control, 10, 20, and 30%) and the spray was applied three times during the plant growth season at 10-day intervals. The second factor was three levels of drought stress; severe drought stress (25% field capacity), moderate drought stress (75% field capacity), and non-stress (100% field capacity). Test results showed that under 20% of methanol and conditions of non-stress there was significant growth of protein content of root and leaf in comparison with the control. Antioxidant enzyme activity was not affected by application of methanol solution spray but leaf antioxidant enzymes activity declined. Under non-stress and methanol concentrations of 10 and 20%, results showed a significant increase in all morphological properties compared with the control treatment. Under conditions of severe and moderate drought stress, level of methanol solution spray did not mitigate the negative effects of drought stress on the studied properties.