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Multiphasic accumulation of nutrients by plants
Author(s) -
NISSEN PER,
FAGERIA NAND K.,
RAYAR ANTONI J.,
HASSAN MOKHTAR M.,
HAI TANG VAN
Publication year - 1980
Publication title -
physiologia plantarum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.351
H-Index - 146
eISSN - 1399-3054
pISSN - 0031-9317
DOI - 10.1111/j.1399-3054.1980.tb02656.x
Subject(s) - nutrient , chemistry , kinetics , ion , horticulture , oryza sativa , orange (colour) , zoology , botany , biophysics , biochemistry , biology , food science , physics , organic chemistry , quantum mechanics , gene
Seedlings of rice ( Oryza sativa ), soybean ( Glycine max ) and sour orange ( Citrus aurantium ) were grown for 20 to 125 days under controlled conditions in nutrient solutions wiht up to 16 different concentrations of NH 4 + , H 2 PO 4 ‐ , K + , Ca 2+ , Mg 2+ or Zn 2+ . Nutrient concentrations differed by up to 4 orders of magnitude (H 2 PO 4 ‐ and Zn 2+ ) and were kept constant or within certain limits by changing solutions daily. Dry weights and concentrations of N, P, K, Ca, Mg or Zn were determined for roots and tops (or roots, stems and leaves). The relationship between tissue concentration of an element and external concentration of the corresponding nutient ion was invariably multiphasic, with phases separated by sharp breaks or jumps. The kinetics of accumulation were similar to those of short‐term uptake of the same ions. Reanalysis of previously published data (including data for Mn 2+ ) for other plants yielded, similarly, bi‐ or multiphasic isotherms for accumulation. Accumulation patterns and growth were in several instances correlated, with separate phases coinciding with regions of poverty adjustment, luxury consumption and toxicity. Implications of multiphasic kinetics of long‐term nutrient accumulation for membrane properties, fluxes and regulation include: (i) Membranes and uptake mechanisms must remain relatively constant throughout the life of the plant with respect to affinities for ions and concentrations at which transitions occur. (ii) Rate‐limitation occurs at the plasmalemma of the root cortical cells. (iii) Uptake is at all times under multiphasic control by the external solution.