Quantification of Aucuba japonica Thunb. CO2 absorption for various moisture conditions

Abstract

The aim of the study was to determine the effect of insufficient moisture supply on the absorption of carbon dioxide by Aucuba japonica Thunb., as well as the dynamics of the growth of phytomass and the amount of CO 2 absorbed by A. japonica at optimal moisture supply during the active growing season from May to September on the Southern coast of the Crimea, a region of dry subtropics. It was revealed that the carbon dioxide absorption rate and the growth rate of A. japonica phytomass begin to decrease when the soil moisture was below 60% of field capacity (FC). The maximum value of CO 2 absorption intensity by A. japonica leaves at optimal soil water supply was 0.95 mg/(cm 2 x day). At a soil water content of 15% FC, the CO 2 absorption rate decreased to 20% of the maximum CO2 absorption value, and the leaf biomass growth rate decreased by 25 times. The maximum monthly average amount of absorbed CO 2 during the period of active vegetation of the A. japonica plant was recorded in May and amounted to 0.83 mg/(cm 2 x day), and the maximum monthly average rate of increase in the volume of leaf phytomass (0.36 cm 3 /day) was noted in August. The phase of the most active growth of A. japonica phytomass occurs in August. It is possible to increase the growth rate of phytomass in August by lowering the air temperature, as well as increasing the relative humidity through drip irrigation.