Scientific publications

The activity of serine proteinases (amidases), cysteine proteinases and trypsin inhibitors was studied in the leaves of cucumber (Cucumis sativus L.) plantlets exposed to low damaging and hardening temperatures. Exposure to a damaging temperature (5 °С) causes rapid and significant rise in the activity of amidases, cysteine proteinases and trypsin inhibitors. During exposure to a hardening temperature (10 °С) we also noted some intensification of the proteinase and inhibitor activity, preceding the rise in the plants' cold resistance. After maximum resistance had been reached however, the activity of amidases and trypsin inhibitors decreases, whereas cysteine proteinase activity remains at the same high level throughout the hardening process. The results suggest cysteine proteinases, amidases and trypsin inhibitors participate in the protective and adaptive response of cucumber plants to both damaging and hardening temperatures.