XV.—The Effect of Certain Factors on the Formation of Root Nodules on Pea Plants in Aseptic Culture

Abstract

The experiments described in the present paper were undertaken as the outcome of an investigation into the possibility of securing nodule formation on leguminous roots cultured separately from the shoots. During that investigation it soon became clear that experiments on whole plants were necessary, in order to test the effect, on the nodulation of the normal whole plant, of certain conditions under which nodulation of root cultures was being attempted. It is thought that these observations on whole plants, though ancillary to the main investigation (which is still in progress), are of sufficient interest to be published separately. The observations are concerned with the effect of the following conditions or treatments on nodule development in a particular variety of pea:—(a) Depriving the plant of light;(b) the presence of sucrose in the rooting medium;(c) the presence of nitrate in the rooting medium; and(d) the presence of certain accessory growth substances, viz. aneurin and nicotinic acid, in the rooting medium.