home    about    browse    search    latest    help 
Login | Create Account

The influence of phosphorus deficiency on growth and nitrogen fixation of white clover plants

Høgh-Jensen, Dr Henning; Schjoerring, Dr Jan K. and Soussana, Dr Jean-Francois (2002) The influence of phosphorus deficiency on growth and nitrogen fixation of white clover plants. Annals of Botany, 90, pp. 745-753.

[img] PDF
Limited to [Registered users only]

260Kb

Online at: http://www.agsci.kvl.dk/~hhj/publications

Summary

The effects of P deficiency on growth, N2-fixation and photosynthesis in white clover (Trifolium repens L.) were investigated using three contrasting relative addition rates of P, or following abrupt withdrawal of the P supply. Responses to a constant below-optimum P supply rate consisted of a decline in N2-fixation per unit root weight and a small reduction in the efficiency with which electrons were allocated to the reduction of N2 in the nodules. Abrupt P removal arrested nodule growth and caused a substantial decline in nitrogenase activity per unit root weight, but not per unit nodule mass.
Similarly, the rate of photosynthesis per unit leaf area was unaffected by abrupt P removal, while the CO2 acquisition for the plant as a whole decreased due to a decline in total leaf area, leaf area per unit leaf weight and utilisation of incoming radiation. These changes followed the decline in tissue P concentrations. The ratio between CO2-fixation and N2-fixation was maintained under short-term P deprivation but increased under long-term low P supply indicating a down-regulation of nodule activity following morphological and growth adjustments. It is concluded that N2-fixation does not limit the growth of clover plants experiencing P deficiency. A low P status induces changes in the relative growth of roots, nodules, and shoots rather than changes in N and/or C uptake rates per unit mass or area of these organs.


EPrint Type:Journal paper
Keywords:fodder legumes, phosphorus, phosphorus deficiency, N2-fixation, nitrogenase activity, white clover, Trifolium repens
Subjects: Crop husbandry > Production systems > Pasture and forage crops
Research affiliation: Denmark > DARCOF I (1996-2001) > I.2 Nitrogen fixation, recycling and leaching in organic cropping systems
Deposited By: Jensen, Dr Henning Høgh
ID Code:286
Deposited On:20 Dec 2002
Last Modified:12 Apr 2010 07:27
Document Language:English
Status:Published
Refereed:Peer-reviewed and accepted

Repository Staff Only: item control page