COMPARATIVE EVALUATION OF PHYSIOLOGICAL AND BIOCHEMICAL PARAMETERS OF SOME FICUS SPECIES AND VARIETIES IN THE CONDITIONS OF SUMMER MOISTURE DEFICIT ON THE SOUTHERN COAST OF CRIMEA

Abstract

The physiological and biochemical parameters of 6 genotypes of genus Ficus species leaves, associated with drought tolerance during the periods of the summer drought on the Southern coast of Crimea were determined. The specific features of the water regime of the species F. carica, F. palmata, F. virgata under the influence of drought factors were revealed. The species F. virgata turned out to be the most sensitive to insufficient water supply. Weak ability to retain moisture and insufficient turgidity was observed in the leaves of the varieties Krymskiy Cherniy and Opylitel Nikitskiy. Leaves of the species F. palmata are characterized by reduced water cut, good water-holding ability and restore tissue turgor at a high level. Protective and adaptive reactions to water stress of the leaves of the Sabrutsiya Rozovaya and Sary Stambulskiy varieties are manifested in the economical use of moisture and protects tissues from excessive dehydration, which ensures a sufficient level of repair for normal physiological processes. It was established that at different periods of the summer season, the biochemical parameters of the studied genotypes at different stages of the experiment varied differently. At the beginning of the summer period, in most of the studied genotypes, the content of proline decreased under full leaves watering, with the restoration of turgidity, it increased, and at the end of the summer, the opposite changes occurred. The activity of peroxidase during restoration of tissue turgor at the beginning of the summer period increased and decreased to a minimum at the end of summer. Catalase activity at the beginning of the summer period decreased with watering the leaves and increased with wilting but at the end of the summer demonstrated no changes with watering and wilting of the leaves and varied in different directions when the turgor was restored. The activity of polyphenol oxidase at the beginning of the summer period at the stage of complete watering and restoration of turgor increased in most genotypes, changed in different directions when wilting, and in late summer it decreased during watering and restoration of turgor and increased after wilting. Despite the amplification of the drought factors, at the end of the summer period the leaves of the studied genotypes preserved the possibility to carry out normal metabolic processes to a greater extent. It was revealed that the proline content, the activity of peroxidase and polyphenol oxidase contribute significantly to the adaptation to drought of the studied genus Ficus species. Analysis of the obtained data allows suggesting that the varieties Sabrutsiya Rozovaya, Sary Stambulskiy and the species F. palmata, which have good water-holding abilities, a high degree of repair after critical dehydration and the ability of the antioxidant system to quickly respond to extreme conditions display the highest adaptive ability to the hydrothermal stress effects, which indicates their relative drought tolerance.