Physiological Investigations on the Banana Plant

Abstract

Banana plants (Musa acuminate cv. Gros Michel) have been grown in sand culture, irrigated with a full nutrient solution and with solutions deficient in each of several nutrient elements. The growth was continued long enough to establish the conditions characteristic of these nutrient treatments. Extracts of leaves, sampled according to their position on the axis, have been made from plants grown in full nutrient solution; these extracts have been examined by chromatographic methods to detect and determine the various nitrogen compounds they contain (A) The relative proportions of the soluble nitrogen compounds of the banana leaf are quite different from those of the fruit and, in response to the deficiency of specified mineral nutrients, both the total amount and the relative composition of the soluble nitrogen fraction are greatly affected. The results are interpreted in terms of the more active accumulation of soluble compounds in young leaves and the maintenance of a low amide (glutamine) level in leaves engaged in protein synthesis. The accumulation of soluble nitrogen compounds when growth and synthesis are arrested, and the relative accumulation of a specified number of nitrogenous substances, due to the lack of a nutrient element, indicates that metabolic blocks in reaction pathways occur. Examples of these effects are given and are related to nutritional deficiency (B).