Effects of Different Amounts of Potassium on Growth and Ash Constituents of Ananas Comosus (l.) Merr.

The data reported in this paper were obtained from plants grown in nutrient solutions supplied with high or low amounts of potassium, namely 205 or 4 mg. per liter but with equal amounts of either nitrateor ammonium-nitrogen. Tops or crowns (vegetative organs produced at the apex of fruits) of uniform size from a single clone were placed in tap water for one month until they had produced about twenty roots of uniform thickness and length. Fourteen plants were then selected and transferred to each of the nutrient solutions described in table I. Each plant was grown in a 4-gallon porcelain crock containing 17 liters of solution which was constantlv aerated and changed regularly at two-week intervals. The plants were grown in these solutions for approximately one year, then all 14 were harvested, weighed, and sectioned according to previously reported techniques (43). The chemical methods employed for the analysis of the tissues were reported in previous publications (39, 40, 41, 42). The statistical significance of the difference of the means of total plant weights between different cultures was calculated by FISHER'S method (6, p. 14). However, the method of CONRAD (5) together with the Z table of LovE (20) was employed for the calculation of the statistical significance of the differences of the means of the various plant constituents between different cultures. In the presentation and discussion of results, various synoptic expressions have been introduced to replace longer appellations often repeated. For instance, the culture with 205 mg. of potassium per liter, or high potassium, will be designated by H-K; and that with 4 mg. of potassium per liter, or low potassium, by L-K. Also, the ammonium-nitrogen series will be referred to as A-n and nitrate-niitrogen as N-n.