STUDY OF STRESS RESISTANCE OF OILSEED RADISH VARIETIES TO SUBZERO TEMPERATURES BY CHLOROPHYLL PHEOPHYTINIZATION
Authors: Tsytsiura Yaroslav 
Published: January 2024

The article highlights the results of studying the peculiarities of the formation of stress resistance of 14 oilseed radish varieties of different ecological and geographical origin to subzero temperatures in the context of 5 basic phenological stages (cotyledon phase (BBCH 10), rosette phase (BBCH 14–16), stemming phase (BBCH 34–36), budding phase (BBCH 50–52) and flowering phase (BBCH 65–67)) with a temperature range of -1.0... -12.0 °C with an experimental step of 1.0 °C decrease based on the tested method of chlorophyll phytophytinization after the physiologically appropriate period of freezing of the calves. The peculiarities of stress reactions in terms of the proportion of phytophytinized leaf surface were investigated based on the processing of scanned images of leaf blades taken from living plants at the appropriate stages of their growth and development. The physiological aspects and literature sources on the assessment of temperature tolerance of cruciferous plant species, in particular radish subspecies, were analyzed and generalizations were made about the adaptive potential of oilseed radish as a species for the conditions of the Right-Bank Forest-Steppe of Ukraine. On the basis of a long-term period of research (2015–2022), the optimal physiological interval of the reaction of different genotypes of oil radish to subzero temperatures was estimated and the most stable phenological phases in relation to the frost resistance of plants were determined by the indicator short-term express reaction of leaf tissues based on the results of their freezing under controlled conditions. A dynamic series of oilseed radish varieties was determined in the direction of increasing the genotype stress resistance to subzero temperatures for the averaged values in the interval from the cotyledon phase to the flowering phase: Lybid, Zhuravka, Ramonta, Ivea, Nika, Prygazhunya, Sabina, Fakel, Rainbow, Alpha, Snizhana, Tambovchanka, IRGSGI Line, Olga. The influence of the total stress of oilseed radish plants based on the value of the hydrothermal coefficient (HTC) during the growing season on the determination of stress resistance to low temperatures was assessed and it was concluded that the combinatorial nature of the formation of pre-adaptive reactions of oilseed radish plants to low temperatures. At the same time, the nature of dynamic changes in the curve of phytophytinization of leaf tissue chlorophyll was determined, which can be used to indirectly analyze deviations in resistance to subzero temperatures during critical periods of growth and development of oilseed radish plants. Additionally, the dynamics of the formation of the leaf chlorophyll phytophytinization index in 14 oilseed radish varieties was evaluated with the detailing of this process at different phenostages of growth and development, and the level of lethality of this process at the corresponding value of the applied freezing temperatures was noted. The article formulates the prospects for further research in the field of optimization of diagnostics of oilseed radish plants stress resistance to subzero temperatures based on the new proline biochemical method of identification at the tissue level.