title: Interactive Effects of CO(2) and O(2) in Soil on Root and Top Growth of Barley and Peas.
abstract: Barley and pea plants were grown under several regimens of different compositions of soil atmosphere, the O(2) concentration varying from 0 to 21% and the CO(2) concentration from 0 to 8%. In absence of CO(2), the effect of O(2) on root length in barley was characterized by equal root lengths within the range of 21 to 7% O(2) and a steep decline between 7 and 0%. In peas, while showing the same general response, the decline occurred between 14 and 7% O(2). Root numbers of the seminal roots of barley decreased already with reduction in O(2) concentration from 21 to 14%. Dry matter production was affected somewhat differently by O(2) and CO(2) concentration. Dry matter production in barley was reduced at 14% O(2) while root length decreased between 7 and 0%. In peas, dry matter production was favored by low CO(2) concentrations except where there was no oxygen. At 21% O(2), increasing CO(2) concentrations did not seem to affect root length up to concentrations of 2% CO(2). At 8% CO(2), root length was decreased. The inter-active effects of CO(2) and O(2) are characterized by a reduced susceptibility to CO(2) at O(2) values below 7%, and a very deleterious effect of 8% CO(2) at 7% O(2).
authors.affiliation: Institute fur Acker- und Pflanzenbau, Landwirtschaftliche Hochschule Hohenheim Stuttgart-Hohenheim, Germany.
authors.forename: G
authors.initials: G
authors.lastname: Geisler