The effect of short-term cold exposure on the change in the concentration of free proline in various birch species in vitro

In natural conditions of growth, forest woody plants constantly face negative environmental factors. Environmentally unfavorable impacts certainly affect the physiological and biochemical processes occurring in plants and lead to the activation of their own protective mechanisms. In recent years, methods of biotechnology (cell and tissue selection) have been increasingly used in the study of adaptive capabilities, as well as the degree of tolerance of plants to abiotic stress factors. In our work, we evaluated the specifics of the reaction of Betula pendula Roth, Betula pendula Roth var. carelica (Mercklin) L. Hämet-Ahti and Betula pubescens Ehrh. in vitro, in particular the change in the level of free proline to low-temperature stress (+4°C) of different duration times. It was found that the highest value of the amino acid content in relation to the control was in the Betula pendula Roth var. carelica Merckl. clones and ranged from 163 to 206%, in the Betula pubescens Ehrh. and Betula pendula Roth clones ranged from 103 to 128% and from 101 to 131%, respectively. Uniformity was noted among the clones of Betula pendula Roth var. carelica Merckl. according to the degree of response to stress. The relationship between the ability of plants to produce more proline and successful adaptation to cold shock was revealed.