Nitrogen resorption and protein degradation during leaf senescence in Chenopodium album grown in different light and nitrogen conditions

Yuko Yasumura, Kouki Hikosaka, Tadaki Hirose

Research output: Contribution to journalArticlepeer-review

29 Citations (Scopus)

Abstract

The extent of nitrogen (N) resorption and the degradability of different protein pools were examined in senescing leaves of an annual herb, Chenopodium album L., grown in two light and N conditions. Both N resorption efficiency (REFF; the proportion of green-leaf N resorbed) and proficiency (RPROF; the level to which leaf N content is reduced by resorption) varied among different growth conditions. During leaf senescence, the majority of soluble and membrane proteins was degraded in all growth conditions. Structural proteins were also highly degradable, implying that no particular protein pool constitutes a non-retranslocatable N pool in the leaf. Leaf carbon/N ratio affected the timing and duration of senescing processes, but it did not regulate the extent of protein degradation or N resorption. Sink-source relationships for N in the plant exerted a more direct influence, depressing N resorption when N sink strength was weakened in the low-light and high-N condition. N resorption was, however, not enhanced in high-light and low-N plants with the strongest N sinks, possibly because it reached an upper limit at some point. We conclude that a combination of several physiological factors determines the extent of N resorption in different growth conditions.

Original languageEnglish
Pages (from-to)409-417
Number of pages9
JournalFunctional Plant Biology
Volume34
Issue number5
DOIs
Publication statusPublished - 2007 May 28

Keywords

  • C/N ratio
  • Membrane protein
  • Sink-source relationships
  • Soluble protein
  • Structural protein

ASJC Scopus subject areas

  • Agronomy and Crop Science
  • Plant Science

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