The Responses of Molinia Caerulea and Erica Tetralix to Soil Aeration and Related Factors: III. Effects of Different Gas Concentrations on Growth in Solution Culture; and General Conclusions

Abstract

Studies of the root distribution of Molinia caerulea and Erica tetralix in relation to the sizes of the soil pores showed that the roots of both the species were confined to pores exceeding 150 ,u diameter. In the soils of the wet-heath sites studied a majority of these large pores contained water for most of the year (Sheikh & Rutter 1969). Therefore, the concentration of the gases dissolved in the soil water (reported by Sheikh 1969b) were of direct importance for the growth of the species in the field. Experiments described below were carried out to study the effects of different concentrations of gases (oxygen, carbon dioxide and hydrogen sulphide), covering the range of concentrations found in the soil water (Sheikh 1969b), on the growth of both Molinia and Erica in water culture.