Features of gas exchange of the squat elm (Ulmus pumila L.) as a factor in the implementation of the climate-regulating function of protective forest plantations

The article presents the results of a study of the physiological parameters of the gas exchange of the leaves of the squat elm (Ulmus pumila L.) in conditions of protective forest belts. The aim of the work was to evaluate the features of Co₂ assimilation, transpiration, and stomatal regulation, as well as their significance for the implementation of the climate-regulating function of protective forest belts. During field measurements, CO₂(A) assimilation, transpiration (E), intercellular CO₂ (Ci) concentration, chamber CO₂ (Ca) concentration, stomatal conductivity (gsw), leaf temperature (Tleaf), water vapor pressure deficiency (VPD) and illumination level (Qimb) were determined. The analysis of the obtained data showed that the parameters of gas exchange are in close functional relationship and reflect the influence of microclimatic conditions and seasonal condition of plants. It has been established that at the end of the growing season, there is a decrease in assimilation activity and a relative predominance of respiratory processes, which limits the absorption of atmospheric CO2. At the same time, the preservation of active stomatal regulation and transpiration indicates the participation of woody plants in the formation of the microclimate of agricultural landscapes. The results obtained emphasize the importance of the physiological characteristics of tree species in assessing the climate-regulating function of protective forest stands and justify the need for similar studies during the active growing season. Keywords: ASSIMILATION, TRANSPIRATION, STOMATAL CONDUCTION, ULMUS PUMILA L, PLANT GAS EXCHANGE, CLIMATE-REGULATING FUNCTION