Hydrogen Sulfide Participation in the Formation of Wheat Seedlings' Heat Resistance Under the Action of Hardening Temperature

The role of hydrogen sulfide (H2S) as a signaling mediator-gasotransmitter in the thermoresistance of plant cells remains poorly understood. The participation of endogenous hydrogen sulfide in heat resistance formation of wheat seedlings (Triticum aestivum L.) caused by short-term exposure to high temperatures was studied. After a 1-min exposure to a temperature of 42 degrees C in roots of wheat seedlings, a transient increase in hydrogen sulfide with a maximum of 1.5 h after heating was observed. At the same time, 24 h after exposure to high temperature, the H2S content in roots decreased to the level of control. The effect of increasing the content of hydrogen sulfide caused by the action of the hardening temperature did not manifest under the treatment of seedlings with scavenger hypotaurine and the inhibitor of L-cysteine desulfhydrase sodium pyruvate. The hardening heating of seedlings caused a rapid increase in the activity of superoxide dismutase (SOD) in the roots and a gradual increase in the activity of catalase and guaiacol peroxidase. The maximum effect of changing the activity of these antioxidant enzymes was observed 24 h after exposure to the hardening temperature. The treatment of seedlings with hypotaurine and sodium pyruvate before hardening heating eliminated the effect of increasing the activity of catalase and guaiacol peroxidase but hardly affected SOD activity. Damaging heating (45 degrees C, 10 min) of seedlings caused an increase in the content of lipid peroxidation (LPO) products in root cells and the subsequent death of a significant part of the seedlings. The preliminary hardening heating significantly increased the heat resistance, decreasing the LPO intensity and the level of seedling death. At the same time, their treatment with the hydrogen sulfide scavenger hypotaurine and the inhibitor of L-cysteine desulfhydrase sodium pyruvate largely neutralized the development of heat resistance caused by hardening heating. A conclusion was made about the role of hydrogen sulfide as a signaling mediator in the regulation of the antioxidant system and the development of seedlings' heat resistance under the action of a hardening temperature.

Automated summary

This study revealed the role of hydrogen sulfide as a signaling mediator in the regulation of antioxidant system and the development of heat resistance in wheat seedlings exposed to high temperatures.