Journal article

Publication year: 1997

Pages: 275-281

Journal: Journal of Plant Nutrition and Soil Science

Volume number: 160

Issue number: 3

ISSN: 0044-3263

DOI Link: https://doi.org/10.1002/jpln.19971600222

Publisher: Wiley-VCH Verlag

Abstract: 
The increase of rhizosphere pH in the course of nitrate nutrition results from H+ consumption in the external medium during uptake of NO3- in a H+ co-transport and from internal OH- production during nitrate reduction. Synthesis of organic acids for NH4+ assimilation as well as strong partial depolarization of membrane potential with NH4+ uptake the important reasons for rhizosphere acidification during ammonium nutrition. Despite differences in proton balance depending on N form, cytoplasmic pH changes are small due to physico-chemical buffering, biochemical pH regulation, H+ inclusion in vacuoles, and H+ release into the rhizosphere.Because of the large capacity for proton excretion the plasmalemma H+ ATPase of root cells plays an essential role during ammonium nutrition. An increase of the kinetic parameter V-max after ammonium nutrition relative to nitrate nutrition suggests that the capacity of H+ release may be adjusted to the particular requirements of ammonium nutrition. Moreover, H+ ATPase is adjusted not only quantitatively but also qualitatively. The increase of the kinetic parameter k(m) as well as the capability of the plasmalemma vesicles in vitro to establish a steeper pH gradient favours the supposition that H+ ATPase isoforms are formed which allow H+ release into the rhizosphere under conditions low pH or poor H+ buffering of the soil. In this respect species differences exist, e.g. between maize (efficient adaptation) and faba bean (poor adaptation).

Harvard Citation style: Schubert, S. and Yan, F. (1997) Nitrate and ammonium nutrition of plants: Effects on acid/base balance and adaptation of root cell plasmalemma H+ ATPase, Journal of Plant Nutrition and Soil Science = Zeitschrift für Pflanzenernährung und Bodenkunde, 160(3), pp. 275-281. https://doi.org/10.1002/jpln.19971600222

APA Citation style: Schubert, S., & Yan, F. (1997). Nitrate and ammonium nutrition of plants: Effects on acid/base balance and adaptation of root cell plasmalemma H+ ATPase. Journal of Plant Nutrition and Soil Science = Zeitschrift für Pflanzenernährung und Bodenkunde. 160(3), 275-281. https://doi.org/10.1002/jpln.19971600222