Nitrogen and carbon costs of soybean and lupin root systems during phosphate starvation

M. R. Le Roux, S. Khan, A. J. Valentine

Research output: Contribution to journalArticlepeer-review

37 Citations (Scopus)

Abstract

Phosphate (P) starvation is one of the most limiting nutrients to N 2 fixation in legumes. Soybeans and lupins present different climatic origins, nodule morphologies and metabolic complexities, which may have various adaptive responses to short-term P starvation. Lupins and soybeans were cultivated hydroponically for 3 weeks. Short-term P starvation was induced for 14 days by switching the P-supply to 2 μM P. During P starvation, the lupins showed a lower decline in nodular P concentrations and maintained their biological N2 fixation (BNF), in contrast to the soybeans. The lupins also maintained their photosynthetic rates and the nodular construction and growth respiration costs under P starvation, whilst soybeans showed a decrease in photosynthetic rates and an increase in nodular construction and growth respiration costs under P starvation. There was a also a shift towards more organic acid synthesis, relative to amino acid synthesis in lupin nodules than soybean nodules under P starvation. The lupins had higher amino acid concentrations in their nodules, whilst the soybean nodules maintained their ureide levels at the expense of a decline in amino acids. These results indicate that lupins may to be better adapted to maintaining BNF during short-term P starvation than the soybeans.

Original languageEnglish
Pages (from-to)102-109
Number of pages8
JournalSymbiosis
Volume48
Issue number1-3
DOIs
Publication statusPublished - 2009
Externally publishedYes

Keywords

  • Carbon costs
  • Lupin
  • Nitrogen metabolism
  • Phosphate
  • Soybean

ASJC Scopus subject areas

  • General Agricultural and Biological Sciences

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