Water regime and potential drought resistance of Ficus carica L.

Abstract

The research was conducted on the basis of collection plantings of the Nikitsky Botanical Gardens - National Scientific Center (Southern Coast of the Crimea) during the summer seasons 2019-2020. Indicators of a number of parameters of the water regime of four Ficus сarica cultivars of different origin were determined, and characteristic features of each genotype were revealed under the influence of arid factors. From May to August, the indicators of leaf tissue water content of the studied genotypes decrease by an average of 8-10 %. During the period of mass fruit ripening, the loss of 10-15 % of moisture by the leaves is a sublethal water deficit for the studied objects, except for Sary Stambulsky cultivar. In the absence of fruit load, the level of permissible sublethal moisture loss increases to 15-20 %, and in 'Sary Stambulsky' can reach 30 %. As a result of a comparative assessment of the complex of physiological indicators, the genotypes 'Sary Stambulsky' and 'Sabrutsia Rozovaya' are potentially adaptive and resistant to hydrothermal stress were identified. The leaves of these cultivars showed a high ability to retain moisture in combination with the ability to perform the most complete tissue repair after critical dehydration. During periods of increased exposure to arid factors, the loss of moisture by leaves in the first hours of wilting in these cultivars did not exceed 20 %. The minimum level of water-retaining forces, as well as in most cases, unsatisfactory turgidity was shown by plants of the Muason (Krymsky Chyorniy) cultivar. Depending on the weather conditions of the summer months, the degree of dehydration of leaf tissues of this genotype after 2 hours of wilting varied in the range of 8-25 %, which indicated a low stability of the water regime. The genotype ‘Opylitel Nikitsky’ was characterized by an average level of drought tolerance.