EFFECTS OF NITROGEN ON GROWTH AND ASH CONSTITUENTS OF ANANAS COMOSUS (L.) MERR.

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Abstract
A. comosus grown in solution cultures supplied with 140 or 2.8 mg. of N per liter, either as nitrate or ammonium produced, after 1 year''s growth, greater wts. in the high-N cultures. N absorption from nutrient solns. was approx. 5 times greater for the high-N cultures in both series. Total ash content per plant was higher in the high-N cultures of the nitrate series and in the low-N cultures of the ammonium series, possibly because of NO3 anions attracting cations and NH4 cations repelling similar cations in the nitrate and ammonium series, respectively. K values per plant were approx. the same for the high-N and low-N cultures in the nitrate series, but in the ammonium series they were approx. 92% greater for the low-N cultures; presumably high NH4 ion concs. caused inhibition of K-ion intake. Ca values per plant were greater for the high-N cultures in the nitrate series. In the ammonium series, Ca values for the high-N cultures were approx. 2/3 as great as in the low-N cultures, resulting, presumably, from the antagonistic effects of high concs. of NH4 ions in the high N cultures. Mg absorption per plant from nutrient solns. was approx. the same for the high- and low-N cultures in the nitrate series, but in the ammonium series it was 1.475 times as great for the low-N cultures. P content per plant was 1.81 and 1.72 times greater for the high-N cultures in the nitrate and ammonium series, respectively. Fe content per plant was greater for the cultures in the nitrate than ammonium series, but in the former series 90.3% of it was in the roots, whereas, in the latter series, the roots of the high-N cultures contained 38.5% of total plant Fe and those of the low-N cultures 89.5%. Translocated iron in the leaves as % of total Fe was 8.6 or 8.8 in the nitrate series and 57.5 or 10% in the ammonium series for the high-N or low-N cultures, respectively.
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