A Vegetation Climatic Unit for Studying the Impact on Higher Plants of an Increased CO2 Concentration in Comparison with the Atmospheric CO2 Concentration.

Malinovsky, A. V.; Akanov, E. N.; Voronin, P. Yu.

An experimental vegetative climatic unit (VCU) consisting of two identical climatic chambers—experimental (CC-1) and control (CC-2)—was developed. The VCU allows long-term cultivation of higher plants under various constant microclimate conditions, moisture supply, and CO2 concentration. The basic scheme of the VCU and its parameters and operation are considered. As a result of a long (50 days) vegetation experiment in the VCU, we evaluated the effect of a double atmospheric CO2 concentration on СО2/Н2О gas exchange, the water status of leaves, and the biological productivity of pea (Pisum sativum L.) plants. The water status of the plant leaves of the experimental and control variants was evaluated based on the water potential value on the surface of the apoplast of the substomatal cavity. Compared to control plants under conditions of double CO2 concentration, a 1.5-fold increase in leaf, stem, and root weight was noted. The preservation of proportional organ growth under growing conditions at a double concentration of atmospheric CO2 in pea varieties with contrasting biological productivity—the highly productive Alpha variety and the unproductive Medovik variety—indicated the absence of varietal specificity of the pea growth reaction to increased CO2. The maximum yield of chlorophyll FSII fluorescence, photosynthetic CO2/H2O-gas exchange of intact leaves, measured at normal CO2 concentration, as well as the water status of the leaves, were the same in the plants of the experimental and control variants of the Medovik variety. With other conditions being equal, a double CO2 concentration of under nonlimiting by the water regime and mineral nutrition conditions of pea plant growing formed a leaf that does not differ from the leaf formed under a normal CO2 concentration. An increase in the biological productivity of peas under these conditions was provided by an increased photosynthetic carboxylation activity under increased atmospheric CO2 concentration and the formation of higher stem and leaf phytomass. As a result, it was concluded that the reaction of the photosynthetic and growth functions of pea plants to long-term cultivation under conditions of a double atmospheric CO2 concentration at nonlimiting by mineral nutrition and water supply conditions did not cause imbalances in growth and development. The reaction of the photosynthetic and growth functions of pea plants was within the physiological norm of the reaction of a pea plant to stress.

PEAS; ATMOSPHERIC carbon dioxide; BIOLOGICAL productivity; CURRICULUM; MINERAL waters; AQUATIC plants; CHLOROPHYLL spectra

Russian Journal of Plant Physiology, 2020, Vol 67, Issue 1, p194

1021-4437

Academic Journal

10.1134/S1021443720010112