The effect of CCC on the nitrogen compounds content in rape plants and their frost hardiness. Relation to the conditions of day-length and temperature

Both CCC and cold (5°C) treatment gave rise to an increased content of the water-soluble proteins in leaf tissue of the winter rape, irrespective of the day length. This effect was accompanied by a decrease of the insoluble nitrogen compounds content, mainly under the LD (the 16 hour day). The applied retardant also stimulated the consumption of the structural compounds induced by low temperature. Low temperature treatment hardened plants more distinctly than the CCC application. The frost hardening effect of CCC and SD (the 8 hour day) was manifested only at 20°C and it disappeared at 5°C. Changes in frost hardiness were not correlated with the changes in the reducing sugar content and in the reducing ability of the studied tissue. The coincident effect of CCC and cold on the reducing sugar content was observed under SD conditions.