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

Abstract

The amts. of chlorophyll and carotenoid pigments in the leaves were not affected by the amts. of K in the cultures. Certain differences encountered were probably due to the different kinds of N in the culture, as the effects of ammonium versus nitrate N were more pronounced on the chlorophyll content of the leaves than those. of high vs. low K. Titrable acidity values reported as citric acid were greater, except in a few cases, in the high- than in the low-K cultures. Ascorbic acid values were greater in the low-K cultures of the nitrate-N series but smaller in the corresponding cultures of the ammonium-N series, indicating that ascorbic acid was affected more by the relations between nitrate vs. ammonium N than by high vs. low K. Total sugar values were greater in the low- than in the high-K cultures, indicating a low rate of polymerization of sugars to starch or other complex carbohydrates in the former cultures. Sucrose as % of total sugars was greater in the high-than low-K cultures and was more abundant in the chloro-phyllose than non-chlorophyllose tissues of the leaves. Starch values were greater in the high- than in the low-K cultures, indicating a higher rate of synthesis in the former cultures, presumably from sugars. Starch depositions were greatest in the transitional and low chlorophyllose sections of the leaves and medial stem sections. Hemicelluloses and celluloses plus lignin were slightly higher in the low- than in the high-K cultures. These data emphasize that adequate amts. of K in the nutrient soln. and consequently in plant tissues are essential for the condensation of reducing sugars to sucrose and starch.