Transpiration of Woody Plants in the Desert Zone of Mangistau

Transpiration of Woody Plants in the Desert Zone of Mangistau

Objective: The present research on the transpiration flow conducted in the arid conditions of Mangistau allowed three groups of introduced species to be distinguished: low transpiration (3 types of trees); average transpiration (7 types of trees and shrubs) and high transpiration (3 types of trees). Methods: The research subjects included 22 introduced species of trees and shrubs of the different geographical origin, degree of biological resistance and growth forms, among them 4 conifers, 15 deciduous trees, and 3 fruit trees. The following methods were applied in the physiological research: the total water content and the transpiration rate. The selection of leaves was made in the middle part of the crown in the 5-10-fold repetition. Results: According to the correlation analysis, a close relationship has been set between the transpiration rate and the water content of leaves. Soil moisture determines from 11.6% to 43.6% of the transpiration rate variation. Reliable at the 5% significance level is the ratio of correlation with the relative moisture and the air temperature. The conjugation with the value of illumination is statistically unreliable. Seasonal dynamics in the majority of introduced species is seen as a unimodal curve with a peak value in June. Three types have been determined for the daily transpiration rhythm: "rising", "falling" and "variable". Conclusion: The intensity of the transpiration process, due to its considerable variability and multifactor nature, cannot be referred to the resistance criteria of woody plants, but at the same time, there is a noticeable connection between the biological stability of introduced species and the coefficient of transpiration variation. With the increase of its values, the resistance of introduced species to the arid habitat conditions is generally enhanced due to their increased ability to the self-regulation of water exchange..