Variations of Residual CO2 and Pressure in Conifer Woody Roots

Abstract

In continuation of works on the determination of cyclic tree-stem CO₂ efflux, vacuum-extracted gas samples of large woody roots of Siberian stone pine and Scots pine are studied. Laser photoacoustic gas analysis was used to obtain chronologies of CO₂ and total pressure of gas components in root rings. Spectral and cross-spectral analyses reveal the cyclic character of variations in the chronologies. Such a behavior of the total pressure and CO₂ content in large roots can testify to possible cyclic diffusion of CO₂ from the roots into soil and then into the atmosphere, which can be considered as a new feature of autotroph respiration. An attempt is made to analyze results of some previous work on a similar subject based on cyclic CO₂ efflux from large roots.