Fractional composition of water in leaf tissues of species and forms of the genus Ulmus L.

Abstract

Optimal conditions of growth and development of species and forms of the genus Ulmus depend on many factors, primarily on the water regime of plants. Optimal water supply is important for rhythmic functioning of physiological processes and optimization of plant productivity. Changes in water exchange occurring in the process of wilting under laboratory conditions are similar to the conditions of open ground during the drought season. However, the indicated method of wilting is not a direct method for assessing drought tolerance, but rather a comparative method. This is due to the fact that it does not take into account the role of the root system, the activity of which in natural conditions is essential. To study the water regime of plants, the laboratory method of wilting is effective, since it is much more efficient than the field method and does not require many years of observation and presence of drought. In order to compare in more detail the drought tolerance of species and forms of the genus Ulmus, the total water content in their leaves was analyzed, fractional analysis of plant water composition was performed, relative turgescence, water deficit and water retention capacity of leaves were determined, which more widely illuminated the response of each taxon to a lack of moisture. These indicators were determined according to the method of M. D. Kushnirenko et al.