[Changes in the activity of proteases and trypsin inhibitors in wheat leaves in the initial period of cold hardening and subsequent dehardening].

The dynamics of amidase, cysteine protease, and trypsin inhibitor activities were studied in the leaves of wheat (Triticum aestivum L.) seedlings grown under controlled conditions (25 degrees C, illuminance 10 kLx, 14-h photoperiod) and subjected to cold hardening (5 degrees C, 10 kLx, 14-h photoperiod). Changes in the activity of amidases and cysteine proteases proved to precede an increase in cold resistance during cold hardening and a decrease in cold resistance after the end of cold hardening. The activity of trypsin inhibitors changed only during cold hardening. It is suggested that amidases, cysteine proteases, and trypsin inhibitors are involved in the cold adaptation of plants.