| Abstract: | The dynamics of cold and heat resistance in a number of coldresistant plant species (potato, meadow fescue, spring and winterwheat) exposed to temperatures from –13 °C to + 50°Chas been studied under controlled environmental conditions.The thermo-resistance of leaves was shown to be constant atcertain temperatures (a range of background temperatures), butit increased (ranges of heat and cold hardening) or decreased(ranges of heat and cold injury) at other temperatures. A gradationof temperatures with respect of ‘thermo-resistance’for these ranges is being proposed. The limits of the rangesvary depending on endogenous (species characteristics, phaseof development) and exogenous factors (environmental conditions).Thus, at gradually rising or falling temperatures the boundariesbetween the ranges of hardening and injury are markedly shiftedtowards more extreme temperatures. Generally, the data showuniformity of responses to extreme temperatures by cold resistantplants; the differences observed between species are quantitative. Key words: Temperature, Cold-resistant plants |
