Does leaf shedding increase the whole-plant carbon gain despite some nitrogen being lost with shedding?

Shimpei Oikawa, Kouki Hikosaka, Tadaki Hirose

Research output: Contribution to journalArticle

26 Citations (Scopus)

Abstract

• When old leaves are shed, part of the nitrogen in the leaf is retranslocated to new leaves. This retranslocation will increase the whole-plant carbon gain when daily C gain : leaf N ratio (daily photosynthetic N-use efficiency, NUE) in the old leaf, expressed as a fraction of NUE in the new leaf, becomes lower than the fraction of leaf N that is resorbed before shedding (RN). • We examined whether plants shed their leaves to increase the whole-plant C gain in accord with this criterion in a dense stand of an annual herb, Xanthium canadense, grown under high (HN) and low (LN) nitrogen availability. • The NUE of a leaf at shedding expressed as a fraction of NUE in a new leaf was nearly equal to the RN in the LN stand, but significantly lower than the RN in the HN stand. Thus shedding of old leaves occurred as expected in the LN stand, whereas in the HN stand, shedding occurred later than expected. • Sensitivity analyses showed that the decline in NUE of a leaf resulted primarily from a reduction in irradiance in the HN stand. On the other hand, it resulted from a reduction in irradiance and also in light-saturated photosynthesis : leaf N content ratio (potential photosynthetic NUE) in the LN stand.

Original languageEnglish
Pages (from-to)617-624
Number of pages8
JournalNew Phytologist
Volume178
Issue number3
DOIs
Publication statusPublished - 2008 May 1

Keywords

  • Carbon gain
  • Leaf canopy
  • Leaf life span
  • Leaf senescence
  • Light availability
  • Nitrogen availability
  • Nitrogen resorption
  • Nitrogen use efficiency (NUE)

ASJC Scopus subject areas

  • Physiology
  • Plant Science

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