Effects of Nitrogen on Chlorophyll, Acidity, Ascorbic Acid, and Carbohydrate Fractions of Ananas comosus (L.) Merr.

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Abstract
The carbohydrate economy of A. comosus was studied in relation to high and low levels of N (140 and 2.8 mg. per liter) supplied to nutrient solns. either as nitrate or ammonium ions with the following results: The % of dry matter in the chlorophyllous regions of healthy leaves was greater for the high-N cultures than for the low-N cultures, but in the non-chlorophyllous (basal) and transitional regions, the reverse was true. Similar values in the stem were greater for the high-N cultures in the nitrate series except in the basal section, but lower for the same cultures in the ammonium series. Chlorophyll concs, in leaf tissue were considerably greater for the high-N cultures. Carotenoids were also greater for the high-N cultures Titrable acidity, reported as citric acid, which by respiratory activity in the chlorophyllous leaf tissues increased during the night and decreased during the day, was greater in the high-N cultures and correlated in general with plant wts. Ascorbic acid, limited mostly to the chlorophyllous regions of the leaves, varied in amts. between young or active and old or mature leaves. The amts. of ascorbic acid in the young or active leaves were greater for high-N cultures; but in the old or mature leaves they were greater for the low-N cultures. Sugars in the leaves and stem were generally greater for the high-N than for the low-N cultures. The gradients of sugar concs, increased from the transitional to the terminal leaf sections for the high-N cultures, but decreased for the low-N cultures except in the very young leaves. Starch of the chlorophyllous sections of the leaves and of the stem, in the nitrate series, was greater for the high-N than low-N cultures, but in the non-chlorophyllous and transitional sections of the leaves, it was greater for the low-N cultures. Nearly all leaf and stem sections in the ammonium series contained more starch for the low-N than high-N cultures. The relations of N to vegetative growth, sugar, starch, and organic acid levels in the tissues of plants were discussed in some detail.