Poor regulation of phosphorus uptake and rhizosphere carboxylates in three phosphorus-hyperaccumulating species of Ptilotus

Lalith B.D. Suriyagoda, M. Tibbett, T. Edmonds-Tibbett, Greg R. Cawthray, Megan H. Ryan

    Research output: Contribution to journalArticlepeer-review

    11 Citations (Scopus)

    Abstract

    © 2015, Springer International Publishing Switzerland. Background and aims: Ptilotus polystachyus occurs in phosphorus (P) – poor soils, but can hyperaccumulate P without toxicity. We examined, in P-poor soils, P accumulation and rhizosphere carboxylates for three Ptilotus species, and carboxylate adsorption and associated P release. Methods: Ptilotus spp. macrocephalus, nobilis and polystachyus were grown in two soils at 40, 100 and 400 mg P kg-1 soil as KH2PO4. After 6 weeks, dry weight (DW), tissue nutrients and rhizosphere carboxylates were determined. Citrate, malate and oxalate adsorption, and associated P release, was investigated in three soils. Results: For all species, shoot DW and carboxylate amount were little affected by increasing P, while green leaves reached ~ 45–60 mg P g-1 DW: tissue P and carbon were negatively correlated. Oxalate was the dominant carboxylate and a large effect of soil type differed with unit (µmol g-1 root DW or rhizosphere soil DW, µmol plant-1). Adsorption was highest for oxalate, but differed with soil type; Freundlich and Langmuir functions generally fitted well. Citrate was the most effective for P release, followed by oxalate. Conclusions: Inability to down-regulate P uptake and rhizosphere carboxylates with increasing P may be characteristic of Ptilotus. The role of these traits in adaptation to P-poor soils merits further investigation.
    Original languageEnglish
    Pages (from-to)145-158
    Number of pages14
    JournalPlant and Soil
    Volume402
    Issue number1-2
    DOIs
    Publication statusPublished - 1 May 2016

    Fingerprint

    Dive into the research topics of 'Poor regulation of phosphorus uptake and rhizosphere carboxylates in three phosphorus-hyperaccumulating species of Ptilotus'. Together they form a unique fingerprint.

    Cite this