IBIS-Flora

Angiosperm Flora of India

pH affects ammonium, nitrate and proton fluxes in the apical region of conifer and soybean roots

Publication Type:Journal Article
Year of Publication:2010
Authors:Hawkins, BJ, Robbins, S
Journal:Physiologia Plantarum
Volume:138
Issue:2
Date Published:2010
ISBN Number:1399-3054
Keywords:glycine, Pinus
Abstract:

The effect of pH on nitrate and ammonium uptake in the high-affinity transport system and low-affinity transport system ranges was compared in two conifers and one crop species. Many conifers grow on acidic soils, thus their preference for ammonium vs nitrate uptake can differ from that of crop plants, and the effect of pH on nitrogen (N) uptake may differ. Proton, ammonium and nitrate net fluxes were measured at seedling root tips and 5, 10, 20 and 30 mm from the tips using a non-invasive microelectrode ion flux measurement system in solutions of 50 or 1500 µM NH4NO3 at pH 4 and 7. In Glycine max and Pinus contorta, efflux of protons was observed at pH 7 while pH 4 resulted in net proton uptake in some root regions. Pseudotsuga menziesii roots consistently showed proton efflux behind the root tip, and thus appear better adapted to maintain proton efflux in acid soils. P. menziesii's ability to maintain ammonium uptake at low pH may relate to its ability to maintain proton efflux. In all three species, net nitrate uptake was greatest at neutral pH. Net ammonium uptake in G. max and net nitrate uptake in P. menziesii were greatly reduced at pH 4, particularly at high N concentration, thus N concentration should be considered when determining optimum pH for N uptake. In P. menziesii and G. max, net N uptake was greater in 1500 than 50 µM NH4NO3 solution, but flux profiles of all ions varied among species.

URL:http://dx.doi.org/10.1111/j.1399-3054.2009.01317.x
Short Title:Physiologia Plantarum
Taxonomic name: 
Fri, 2014-01-24 22:40 -- admin
https://secure.gravatar.com/avatar/5ade1b012674ce3dd941e2ea5dd15cc1.jpg?d=https%3A//flora.indianbiodiversity.org/sites/all/modules/patches/contrib/gravatar/avatar.png&s=100&r=G
Scratchpads developed and conceived by (alphabetical): Ed Baker, Katherine Bouton Alice Heaton Dimitris Koureas, Laurence Livermore, Dave Roberts, Simon Rycroft, Ben Scott, Vince Smith