Biotechnological approach for protection of corn plants against temperature stress

Because of the environmental stress conditions, lots of plants die or their productivity decrease. Adverse environmental conditions create some stresses on plants. Freezing, drought, UV, salinity, heavy metals, too high and low temperatures are the examples of the stresses. The stresses will be even worse in the future because of the global climate change. As a result, number of plants which are the sources of the oxygen will decrease dramatically. Protection of the plants is one of the most important issues for living. Heat is one of the abiotic stresses and it is simply defined as rise in air and soil temperature. In the study, some different ways were tried against heat stress for increasing crop productivity under high temperature (30̊ C). Spermidine, putrescine dihydrochloride, salicylic acid, ascorbic acid and kaolin and their different concentrations were used and their effects on plants against heat stress were investigated. According to the result, the treatments show positive effects on plant development in terms of many parameters. 10 mM kaolin application was the most effective way for increasing mineral content, SPAD value, intercellular CO2 amount, sucrose amount and for decreasing MDA content and POD activity. 5 mM ascorbic acid application was the most effective way for increasing amino acid content and for decreasing CAT, SOD activity H2O2 content. 1 mM salicylic acid application was the most effective way for increasing LRWC and organic acid content. 0.25 mM salicylic acid application was also the most effective way for increasing amino acid content. 2.5 mM putrescine dihydrochloride was also the most effective way for decreasing H2O2 content. 2.5 mM spermidine solution was the most effective was for increasing net photosynthesis rate, stomatal conductance and transpiration rate. Yield was the most important parameter and it increased about 190 percent with the application of 2 mM spermidine. Also, with the 10 mM kaolin application, many parameters like mineral content, photosynthesis antioxidant enzyme activity was affected positively while 2 mM spermidine was the best way for only increasing yield.