Photosynthesis Research

, Volume 41, Issue 3, pp 451–463

Xanthophyll cycle components and capacity for non-radiative energy dissipation in sun and shade leaves ofLigustrum ovalifolium exposed to conditions limiting photosynthesis

  • Enrico Brugnoli
  • Alessandra Cona
  • Marco Lauteri
Regular Paper

DOI: 10.1007/BF02183047

Cite this article as:
Brugnoli, E., Cona, A. & Lauteri, M. Photosynth Res (1994) 41: 451. doi:10.1007/BF02183047

Abstract

The relationships between photosynthetic efficiency, non-radiative energy dissipation and carotenoid composition were studied in leaves ofLigustrum ovalifolium developed either under full sunlight or in the shade. Sun leaves contained a much greater pool of xanthophyll cycle components than shade leaves. The rate of non-radiative energy dissipation, measured as non-photochemical fluorescence quenching (NPQ), was strictly related to the deepoxidation state (DPS) of xanthophyll cycle components in both sun and shade leaves, indicating that zeaxanthin (Z) and antheraxanthin (A) are involved in the development of NPQ. Under extreme conditions of excessive energy, sun leaves showed higher maximum DPS than shade leaves. Therefore, sun leaves contained not only a greater pool of xanthophyll cycle components but also a higher proportion of violaxanthin (V) actually photoconvertible to A and Z, compared to shade leaves. Both these effects contributed to the higher NPQ in sun versus shade leaves. The amount of photoconvertible V was strongly related to chla/b ratio and inversely to leaf neoxanthin content. This evidence indicates that the amount of photoconvertible V may be dependent on the degree of thylakoid membrane appression and on the organization of chlorophyll-protein complexes, and possible explanations are discussed. Exposure to chilling temperatures caused a strong decline in the photon yield of photosynthesis and in the intrinsic efficiency of PS II photochemistry in sun leaves, but little effects in shade leaves. These effects were accompanied by increases in the pool of xanthophyll cycle components and in DPS, more pronounced in sun than in shade leaves. This corroborates the view that Z and A may play a photoprotective role under unfavorable conditions. In addition to the xanthophyll-related non-radiative energy dissipation, a slow relaxing component of NPQ, independent from A and Z concentrations, has been found in leaves exposed to low temperature and high light. This quenching component may be attributed either to other regulatory mechanism of PS II efficiency or to photoinactivation.

Key words

carotenoid chilling high-light stress photoconvertible violaxanthin sun-shade acclimation xanthophyll cycle 

Abbreviations

A

antheraxanthin

CP

chlorophyll-protein

DPS

deepoxidation state of xanthophyll cycle components

F, Fm

chlorophyll fluorescence yield at actual, full closure of the PS II centers

Fm′

chlorophyll fluorescence yield at full closure of PS II reaction centers in the presence of non-photochemical quenching

Fv

variable fluorescence

LHCII

light harvesting complex of PS II

PFD

photon flux density

PS II

Photosystem II

NPQ

Stern-Volmer non-photochemical chlorophyll fluorescence quenching

NRD

non-radiative energy dissipation

V

violaxanthin

Z

zeaxanthin

Φ

photon yield of photosynthesis

Φ

efficiency of PS II at actual closure of reaction centers

Copyright information

© Kluwer Academic Publishers 1994

Authors and Affiliations

  • Enrico Brugnoli
    • 1
  • Alessandra Cona
    • 1
  • Marco Lauteri
    • 1
  1. 1.C.N.R.Istituto per l'AgroselvicolturaPorano (TR)Italy

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