SEPARATE AND COMBINED EFFECT OF LOW TEMPERATURE AND CADMIUM ON SOME PHYSIOLOGICAL INDICATORS OF WHEAT

Abstract

The effects of separate and combined impact of low temperature (4°C) and cadmium (100 µM) on the dynamics of a number of indicators of water metabolism, photosynthetic activity and cold tolerance of wheat (Triticum aestivum L.) were investigated. It was found that the complex of physiological changes occur in the cells and tissues of wheat during stress treatment, however, their dynamics dependent of the type of stress factor. In particular, low temperature causes the number of protective and adaptive changes in wheat cells: the increasing of mesophyll cells size, number of chloroplasts in them and chlorophyll content in the light-harvesting complex, the stabilizing of the rate of photosynthesis, transpiration and stomatal conductance of leaves, the reducing of the water content of tissues took place under conditions of low temperature. Probably these changes contribute to improve the cold tolerance of plants. In the presence of cadmium cold tolerance of leaves decreased and toxic effects of cadmium developed: mesophyll cells growth stopped, the number of chloroplasts in them reduced, the content of photosynthetic pigments in the leaves decreased, there were signs of chlorosis. In the conditions of the combined action of stress factors cadmium prevented the development of some adaptive responses to temperature (increase in size of cells and number of chloroplasts in their), low temperature partially eliminated the toxic effects of cadmium on pigment apparatus of plants and prevented the development of chlorosis. Thus, the results of the studies show that response of wheat plants to the combined effect of low temperature and cadmium is significantly different from their reaction to the action of these stressors separately.

Keywords

• triticum aestivum l.
• низкая температура
• кадмий
• водный обмен
• фотосинтетический аппарат
• холодоустойчивость