Influx and efflux of amino acids from Zea mays L. roots and their implications for N nutrition and the rhizosphere
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The aim of the study was to investigate the ability of Zea mays L. roots to regulate the amount of free amino acids present in the rhizosphere. The active uptake of amino acids was shown to conform to Michaelis-Menten kinetics. Comparison of amino acid-N and NO3-N kinetic parameters and soil solution concentrations showed that root uptake of free amino acids from soil may contribute significantly to a plant's N budget. The influx of amino acids also helps to minimize net C/N losses to the soil, and is therefore important in regulating the size of the rhizosphere microbial population. Experimental data and a computer simulation model of amino acid influx/efflux in a sterile solution culture, showed that roots were capable of re-sorping over 90% of the amino acids previously lost into solution as a result of passive diffusion.
Key wordsamino acids maize rhizosphere root exudates
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- Barber S 1984 Soil nutrient bioavailability: A Mechanistic approach. Wiley-Interscience, New York. 398p.Google Scholar
- Darrah P R 1991 J. Soil. Sci. 42, 421–436.Google Scholar
- Guckert A, Chavanon M, Mench M, Morel M and Villemin G 1991 In Plant Roots and Their Environment. Eds. B L McMichael and H Persson. pp 449–455. Elsevier Science Publishers B.V.Google Scholar
- Jones D L and Darrah P R 1992 Plant and Soil 143, 259–266.Google Scholar
- Jones D L and Darrah P R 1993a Plant and Soil in press.Google Scholar
- Jones D L and Darrah P R 1993b Plant Physiol. submitted.Google Scholar
- Jones D L and Darrah P R 1993c Plant and Soil. submitted.Google Scholar
- Moore S and Stein W H 1948 J. Biol. Chem. 176, 367–388.Google Scholar
- Sorensen L H 1975 Soil Biol. Biochem. 7, 171–177.Google Scholar
- Uren N C and Reisenauer H M 1988 Adv. Plant Nut. 3, 79–114.Google Scholar