Endogenous content of abscisic acid was studied in a set of two winter cultivars of barleys (Lunet, Cenader), one spring cultivar (Akcent) and five winter cultivars of wheat (Mironovská, Samanta, Šárka, Zdar, Apache) and one spring cultivar (Leguan) in the course of cold hardening of hydroponically grown plants. Freezing tolerance was also determined in all barley and wheat cultivars under study. In none of the barley varieties did cold hardening of plants induce any significant change in abscisic acid content. In wheat plants exposed to cold hardening, the cultivars Apache and Leguan showed a slight transitory increase in abscisic acid content. Abscisic acid content in leaves was very similar in the other wheat cultivars. Neither in barley nor in wheat was the level of freezing tolerance associated with endogenous abscisic acid content or with its transitory changes during cold hardening.
VARIATIONS IN FOLIAR CARBON ISOTOPE COMPOSITION AND ADAPTIVE STRATEGIES OF CAREX KORSHINSKYI ALONG A SOIL MOISTURE GRADIENT