ON THE NATURE OF CO2 EXCHANGE IN THE STEM OF SCOTCH PINE

The nature of CO2 exchange in the stem of pine (Pinus sylvestris L.) was analyzed on the basis of experimental data and evidence in the literature. The following basic questions were examined here: source of carbon dioxide in the stem: influence of the main physical factors on solubility and concentration of separate chemical forms of carbon dioxide in stem tissues; characteristics of CO2 diffusion in stem tissues of different anatomical structure; and criteria that in certain measure make it possible to interpret CO2 exchange of the stem as its respiration. All of this enabled us to conclude that carbon dioxide exchange of the pine stem in regard to its nature primarily reflects its respiration.