EFFECTS OF POTASSIUM ON CHLOROPHYLL, ACIDITY, ASCORBIC ACID, AND CARBOHYDRATES OF ANANAS COMOSUS (L.) MERR

Abstract

The amounts of chlorophyll and carotenoid pigments in pineapple leaves were not affected by the amounts of potassium in the cultures. Titrable acidity values reported as citric acid were greater, except in a few cases, in the high- than in the low-potassium cultures. Ascorbic acid values were greater in the low-potassium cultures of the nitrate-nitrogen series but smaller in the corrsponding cultures of the ammonium-nitrogen series. Total sugar values were greater in the low- than in the high-potassium cultures. Sucrose as percentage of total sugars was greater in the high- than low-potassium cultures and was more abundant in the chlorophyllose than non-chlorophyllose tissues of the leaves. Starch values were greater in the high- than in the low-potassium cultures. Starch depositions were greatest in the transitional and low chlorphyllose sections of the leaves and medial stem sections. Hemicelluloses and celluloses plus lignin were slightly higher in the low- than in the high-potassium cultures. The data emphasize that adequate amounts of potassium in the nutrient solution and consequently in plant tissues are essential for the condensation of reducing sugars to sucrose and starch. [From authors' summary.]