Plant Physiol. Illumina
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH
QUICK SEARCH:   [advanced]


     

Plant Physiology Preview
Published on April 30, 2004; 10.1104/pp.103.035659

This Article
Right arrow Full Text (Plant Physiology Preview (PDF))
Right arrow All Versions of this Article:
135/1/549    most recent
pp.103.035659v1
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in Web of Science
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via CrossRef
Right arrow Citing Articles via Web of Science (20)
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Shane, M. W.
Right arrow Articles by Lambers, H.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Shane, M. W.
Right arrow Articles by Lambers, H.
Agricola
Right arrow Articles by Shane, M. W.
Right arrow Articles by Lambers, H.

Received November 2, 2003
Returned for revision February 16, 2004
Accepted February 22, 2004

Developmental Physiology of Cluster-Root Carboxylate Synthesis and Exudation in Harsh Hakea. Expression of Phosphoenolpyruvate Carboxylase and the Alternative Oxidase

Michael W. Shane *, Michael D. Cramer , Sachiko Funayama-Noguchi , Gregory R. Cawthray , A. Harvey Millar , David A. Day , and Hans Lambers

School of Plant Biology, Faculty of Natural and Agricultural Sciences (M.W.S., M.D.C., S.F.-N., G.R.C., H.L.); and School of Biomedical and Chemical Sciences, Faculty of Life and Physical Sciences (H.M., D.A.D.), The University of Western Australia, Crawley, Western Australia 6009, Australia

* Corresponding author; email: mshane{at}agric.uwa.edu.au.

Harsh hakea (Hakea prostrata R.Br.) is a member of the Proteaceae family, which is highly represented on the extremely nutrient-impoverished soils in southwest Australia. When phosphorus is limiting, harsh hakea develops proteoid or cluster roots that release carboxylates that mobilize sparingly soluble phosphate in the rhizosphere. To investigate the physiology underlying the synthesis and exudation of carboxylates from cluster roots in Proteaceae, we measured O2 consumption, CO2 release, internal carboxylate concentrations and carboxylate exudation, and the abundance of the enzymes phosphoenolpyruvate carboxylase and alternative oxidase (AOX) over a 3-week time course of cluster-root development. Peak rates of citrate and malate exudation were observed from 12- to 13-d-old cluster roots, preceded by a reduction in cluster-root total protein levels and a reduced rate of O2 consumption. In harsh hakea, phosphoenolpyruvate carboxylase expression was relatively constant in cluster roots, regardless of developmental stage. During cluster-root maturation, however, the expression of AOX protein increased prior to the time when citrate and malate exudation peaked. This increase in AOX protein levels is presumably needed to allow a greater flow of electrons through the mitochondrial electron transport chain in the absence of rapid ATP turnover. Citrate and isocitrate synthesis and accumulation contributed in a major way to the subsequent burst of citrate and malate exudation. Phosphorus accumulated by harsh hakea cluster roots was remobilized during senescence as part of their efficient P cycling strategy for growth on nutrient impoverished soils.




This article has been cited by other articles:


Home page
 ANN BOT (LOND)Home page
H. LAMBERS, M. W. SHANE, M. D. CRAMER, S. J. PEARSE, and E. J. VENEKLAAS
Root Structure and Functioning for Efficient Acquisition of Phosphorus: Matching Morphological and Physiological Traits
Ann. Bot., October 1, 2006; 98(4): 693 - 713.
[Abstract] [Full Text] [PDF]

Home page
 Plant Physiol.Home page
J. R. Watling, S. A. Robinson, and R. S. Seymour
Contribution of the Alternative Pathway to Respiration during Thermogenesis in Flowers of the Sacred Lotus
Plant Physiology, April 1, 2006; 140(4): 1367 - 1373.
[Abstract] [Full Text] [PDF]

Home page
 J Exp BotHome page
M. W. Shane and H. Lambers
Systemic suppression of cluster-root formation and net P-uptake rates in Grevillea crithmifolia at elevated P supply: a proteacean with resistance for developing symptoms of 'P toxicity'
J. Exp. Bot., January 1, 2006; 57(2): 413 - 423.
[Abstract] [Full Text] [PDF]


HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH
ASPB Publications PLANT PHYSIOLOGY® THE PLANT CELL
Copyright © 2004 by the American Society of Plant Biologists