The influence of plants on atmospheric carbon monoxide and dinitrogen oxide

It is shown by laboratory experiments and extensivein-situ measurements that higher plants (Vicia faba, Platanus acerifolia, Fagus silvatica, andPinus silvestris) produce carbon monoxide. The measurements were carried out under natural conditions with respect to the concentrations of O₂ and H₂O, and temperature. The CO₂- and CO-mixing ratios were varied in the ranges 350 to 530 ppm and 3–270 ppb, respectively. The CO-production rates were found to be light dependent with an average value per cm² of leaf area of 3×10^–13 g/sec for a radiation intensity of 5×10⁴ erg/cm² sec. The production rates are independent of the CO₂- and CO-mixing ratios employed in the test atmosphere. Considering the production rate of 3×10^–13 g/cm² sec to be representative for global conditions the total CO-production by plants is estimated to be 0.5–1.0×10¹⁴ g/year. In contrast to carbon monoxide atmospheric dinitrogen oxide is not influenced by plants in the same manner.