GROWTH OF ANANAS COMOSUS (L.) MERR., AT DIFFERENT LEVELS OF MINERAL NUTRITION UNDER GREENHOUSE AND FIELD CONDITIONS. II. CHEMICAL COMPOSITION OF THE TISSUES AT DIFFERENT GROWTH INTERVALS

Abstract

This report supplements the earlier report (13) which discussed the growth rates, water and mineral nutrient intake by the same group of plants. The data herein considered deal with the chemical composition of the leaf and stem tissues at different growth intervals of pineapple plants grown in nutrient solutions in the greenhouse and in soil under field conditions with different amounts of nitrate, potassium, and calcium.The plant tissues were analyzed for total nitrogen, soluble organic nitrogen, potassium, calcium, reducing and total sugars; the latter hydrolyzed by invertase. The methods for potassium and calcium were reported in a previous publication (9). Total nitrogen and soluble organic nitrogen were determined by the Kjeldahl procedure, using selenium oxychloride as catalyst in the oxidation of organic matter. The fractionation of total and soluble organic nitrogen was conducted according to technique reported previously (7,8). Reducing sugars, total sugars, and sucrose, the latter by the difference between total and reducing sugars after hydrolysis with invertase, were determined according to the method of QUISUMBING and THOMAS (6). Starch was determined by the method of PUCHER and VICKERY (5). Results GREENHOUSE PLANTSThe chemical composition of the nutrient solutions in the different cultures, reported previously (13)

Pineapple Chlorosis in Relation to Iron and Nitrogen

“…In this study the relationship of chlorophyll concentrations to photosynthesis was measured by total plant and fruit weights, in addition to the average concentrations of total sugars and starch. The results (fig 10) show that the concentrations of sugars in the chlorophyllous distal seetions 3, 4, and 5 were greater for the "Plus Fe" than for the "AMinus Fe" cultures, while in the nonchlorophvllous proximal sections 1 and 2, they were reversed (29).…”

“…Chlorophyll and carotenoid concentrations were found to vary greatly in different areas, or sections, along the length of pineapple leaves (20,22,26,27,28). The measurements reported herein for the "Plus Fe" and "Minus Fe" cultures were made in comparable leaf areas.…”

Interaction of Factors Affecting Yield

“…It has been applied to an exceedingly wide range of crops : pasture (181), forage (144) , root (254,257) and tuber crops (138), bananas (242), sugar cane (89,101,105), pineapple (156,157,197,209), rice (109), cereal grains (218), corn (140), citrus (54,149,161,260), brambles (35), grapes (12,199), tea (284), coffee and other orchards (13,16,128,241), rubber (206), oil (43,44,175,177,201), nuts (77), cotton (97,123,140), flowers (139), and stands of forest trees (117,118,162,164,224). The systems developed range from the com prehensive crop logging system of sugar cane (59,64,65), where nutrients as well as tissue moisture and carbohydrate levels are followed on the basis of samples every five weeks throughout the life of the sugar cane crop, to single sample analysis per crop year, a rather common procedure with many crops.…”