Influence of thermal hardening on the carbohydrate metabolism of wheat and beans seedlings in adaptation to hyperthermia

The content of basic carbohydrates (glucose and sucrose) and the activity of the key enzymes of carbohydrate metabolism (amylase and invertase) in the process of wheat and bean seedlings adaptation to hyperthermia (+ 40°C 3 days) in the presence or absence of heat hardening (+ 37°C, 3 h) were studied. It was established that preliminary thermal hardening leads to a significant increase in the amount of glucose and sucrose in both plants under conditions of subsequent hyperthermia. At the same time, in wheat, amylase and invertase activities were reduced, whereas in beans, amylase decreased, invertase activity increased significantly. This suggests that the heat hardening of both cultures is based on an increased level of soluble sugars, which is achieved by different mechanisms: in wheat, due to an increase in the intensity of photosynthesis, and in beans, due to inhibition of sucrose outflow to the phloem.