Dynamics of intercellular water transfer in the roots of intact Zea mays L. plants under elevated concentrations of atmospheric CO.

In this study, the effect of atmospheric carbon dioxide concentration increase on the dynamics of radial intercellular water transfer in the root suction zone of intact maize plants was evaluated. To this end, a unique growth chamber, associated with H NMR PGMF (proton nuclear magnetic resonance with a pulsed gradient of the magnetic field) equipment, was used. As the atmospheric CO concentration increased up to 800 ppm and 1200 ppm, and the intensity of water transfer in the roots significantly decreased. The average effective water diffusion coefficient (D) and the water permeability in root cells (P) decreased by approximately 30-35% within 5-6 h after the increase in CO concentration. At a higher concentration of CO, 1200 ppm, the rate of decrease in water permeability increased. After a day of exposure to elevated CO the intensity of water transfer was partially restored but remained below the control level (before CO enrichment) over the next 7 days. Inhibitory analysis showed that root cell aquaporins (AQPs) made a significant contribution to the observed decrease in the intensity of water transport in the roots. The decrease in water permeability of root cells under elevated CO concentrations possibly occurs due to the regulatory decrease in water conductivity of AQPs via shoot-to-root long-distance signaling.