Influence of Environmental Conditions on Carbon and Water Exchange Processes in Aucuba japonica Thunb.

Abstract

In the context of climate change and deterioration of environmental conditions in urbanized regions, the study of the ecophysiological features of woody plants in order to select them for effective landscaping is of particular relevance. In this paper, the influence of abiotic factors on the daily variability of CO2/H2O gas exchange of Aucuba japonica Thunb., 1783 during the growing season on the Southern Coast of the Crimea is investigated. A photosynthesis monitor RTM-48A and a phytomonitor PM-11z (Bio Instruments S.R.L., Moldova) were used to measure gas exchange and environmental parameters. The analysis of the seasonal dynamics of carbon dioxide gas exchange showed a high sensitivity of the processes of carbon and water exchange of A. japonica to the prevailing environmental conditions, which cause fluctuations in the value of the daily carbon dioxide absorption more than four times. The preservation of the positive carbon balance of A. japonica under hydrothermal stress indicates the significant potential of plants for optimizing the urban ecosystems of the southern regions of Russia. Based on the revealed relationships a nonlinear regression equation is constructed, which can be used to predict the assimilation activity of A. japonica under current environmental conditions and expected climate changes.