EFFECTS OF IRON ON CHLOROPHYLLOUS PIGMENTS, ASCORBIC ACID, ACIDITY AND CARBOHYDRATES OF ANANAS COMOSUS (L.) MERR., SUPPLIED WITH NITRATE OR AMMONIUM SALTS

Abstract

Chlorophyll and cartenold pigments were higher in the leaves of the plus-iron than minus-iron cultures. Titrable acidity gradients reported as citric acid, increased from the basal to the terminal sections of the leaves of the plants of all cultures. Ascorbic acid was almost limited to the chlorophyllous sections of the leaves although the amounts present were not directly proportional to those of chlorophyll in the plants of the different cultures. Sugars were found in greater amounts in the leaves of the "old", "mature", and "active" groups of the plus-iron than minus-iron cultures. The amounts of levulose were slightly higher in the leaves of the minus-iron than plus-iron cultures of the nitrate-nitrogen series. Starch was consistently higher in the stem of the plus than minus-iron cultures, the former containing 101.3% more starch for the ammonium series and 33.2% more for the nitrate series. The plants of the nitrate-nitrogen series contained 161.6% more starch for the plus-iron and 295.0% for the minus-iron cultures than of the ammonium-nitrogen series. The differences in total hemicellulose sugars between the plants of the plus- and minus-iron cultures were slight, with the plants of the former cultures containing, in most sections, greater amounts than the latter. The amounts of cellulose were higher in the transitional sections which bear the strain for the erect position of the young leaves and reclined position of the mature leaves. Lignin was generally high in those parts of the plant containing great amounts of fibrovascular tissues such as the roots, basal sections of the stem and terminal sections of the leaves. The amounts of both celluloses and lignin were affected only slightly by the different treatments and behaved in this respect like the hemicelluloses.