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  • Author or Editor: Fayek B. Negm x
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Abstract

A preparative column consisting of 1 ml each polyvinylpyrrolidone, Amberlite IRA-45 in the acetate form, and Dowex 50W in the acid form removed 98% to 99% of the cations and phenolics from leaf extracts of Euonymus japonica Thunb. and from standard solutions of magnesium acetate and catechin. Sucrose inversion occurred when 2 or 3 ml of cation exchange resin were used or when 1 ml was used at a flow rate of 0.1 ml/min. Sucrose inversion was inversely related to column flow rate.

Open Access

Abstract

Rooted cuttings of Chrysanthemum × morifolium Ramat. ‘Gt. #4 Indianapolis White’ were grown in a greenhouse in a sand culture and supplied with either 3.75 or 15.0 mm NO 3 . Changes in dry matter, reduced N and NO 3 of the leaves, stems (plus petioles), roots, and inflorescence and in vivo NO 3 reductase activity (NRA) of leaves were determined at various stages of development. A decrease in the NO 3 supply caused a decrease in the accumulation of plant dry matter, reduced N and NO 3 . Plants receiving 3.75 mm NO 3 remobilized a significant amount of reduced N from vegetative tissues during inflorescence development, suggesting that newly absorbed N was inadequate to supply the flower. At both NO 3 fertilization levels, the NO 3 content of the leaves and stems declined during inflorescence development, suggesting an increased dependence on previously accumulated NO 3 for reduction. The highest NRA of the leaves (3.4 μmoles NO2 gFW−1 hr−1) was associated with early vegetative growth. NRA, however, was detectable throughout plant development. Nitrate reductase activity was greater at 15 mM NO 3 than at 3.75 mM NO 3 during vegetative growth and visible bud stages, but not at later stages of growth.

Open Access