Effect of Temperature on Lipoxygenase Activity in Varieties of Triticum aestivum L. Differing in Resistance to Abiotic Stressors

Effects of high (+400C, 2 h) and low positive (+40C, 2 h) temperatures on lipoxygenase activity in varieties of Triticum aestivum L. differing in their resistance to abiotic stressors have been analyzed. For the first time 9-lipoxygenase activity was identified in the overground part and roots of 14-day-old plants of the three new winter wheat varieties selected in Ukraine. Increase in lipoxygenase activity both in the plant overground and root parts turned out to be a non-specific response to hyperthermia and hypothermia. Intensity of response to a heat stress was significantly higher than that of cold effects. In the overground part of the heat-resistant variety Yatran 60 a short-term hyperthermia caused a fourfold increase in the activity of lipoxygenase with рНопр5.5 and six-fold increase in lipoxygenase activity with рНопт 6.3. The activity of lipoxygenase with рНопр in roots increased one and the half times. The activity of lipoxygenase with рНопт 7.0 in the overground part of the cold-resistant variety Volodarka exposed to hyperthermia increased one and a half times and that of lipoxygenase with рНопт 6.0 – 1.3 times, and in roots the activity of lipoxygenase with рНопт 6.5 increased three time. In the overground part of the ecologically flexible variety Podolyanka exposed to a short-term hyperthermia the activity of lipoxygenase with рНопт 7.5 increased one and the half times, lipoxygenase with рНопт 5,5 – 1.7 times, and in roots the activity of lipoxygenase with рНопт 6,5 – almost two times. The most pronounced response to hyperthermia occurred in the heat-resistant variety Yatran 60. Prospects for use of lipoxygenase as a plant resistance marker as well as possible involvement of lipoxygenase activity in the formation of cell adaptation mechanisms are discussed.