Effects of growth light and nitrogen nutrition on the organization of the photosynthetic apparatus in leaves of a C4 plant, Amaranthus cruentus

Youshi Tazoe, Ko Noguchi, Ichiro Terashima

Research output: Contribution to journalArticle

49 Citations (Scopus)

Abstract

Properties of C4 photosynthesis were examined in Amaranthus cruentus L. (NAD-malic enzyme (ME) subtype, dicot) grown under different light and nitrogen (N) conditions, from the viewpoint of N investment into their photosynthetic components. In low-light (LL) leaves, chlorophyll content per leaf area was greater and chlorophyll a/b ratio was lower than in high-light (HL) leaves. These indicate that LL leaves invest more N into their light-harvesting systems. However, this N investment did not contribute to the increase in the quantum yield of photosynthesis on the incident photon flux density (PFD) basis (Qi) in LL leaves. N allocation to ribulose 1,5-bisphosphate carboxylase/oxygenase (Rubisco) was significantly higher in HL-high N (HN) leaves than in other leaves. On the other hand, N allocation to C4 enzymes [phosphoenolpyruvate carboxylase (PEPC) and pyruvate Pi dikinase (PPDK)] was unaffected by the growth conditions. Maximum photosynthetic rates (Pmax) per Rubisco content were similar irrespective of the growth light treatments. Carbon isotope ratios (δ13C) in the leaf dry matter were more negative in LL leaves than in HL leaves (LL = -19.3‰, HL = -16.0‰) and independent of leaf N. Vein density was highest in HL-HN leaves, and leaf thickness was unaffected by the growth light treatments. From these results, we conclude that A. cruentus leaves would not acclimate efficiently to low growth light.

Original languageEnglish
Pages (from-to)691-700
Number of pages10
JournalPlant, Cell and Environment
Volume29
Issue number4
DOIs
Publication statusPublished - 2006 Apr 1
Externally publishedYes

Keywords

  • Carbon isotope ratio
  • Phosphoenolpyruvate carboxylase (PEPC)
  • Quantum yield
  • Ribulose 1,5-bisphosphate carboxylase/oxygenase (Rubisco)

ASJC Scopus subject areas

  • Physiology
  • Plant Science

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