Photoabatement by anthocyanin shields photosynthetic systems from light stress

Smillie, Robert M. and Hetherington, Suzan E. (1999) Photoabatement by anthocyanin shields photosynthetic systems from light stress. Photosynthetica, 36 3: 451-463. doi:10.1023/A:1007084321859

Author Smillie, Robert M.
Hetherington, Suzan E.
Title Photoabatement by anthocyanin shields photosynthetic systems from light stress
Journal name Photosynthetica   Check publisher's open access policy
ISSN 0300-3604
Publication date 1999-03-01
Sub-type Article (original research)
DOI 10.1023/A:1007084321859
Volume 36
Issue 3
Start page 451
End page 463
Total pages 13
Place of publication Praha, Czechoslovakia
Publisher Kluwer
Language eng
Subject C1
270402 Plant Physiology
620209 Ornamentals, Australian natives and nursery plants
Formatted abstract
Leaves and other chlorophyllous tissues of plants often show transient or permanent anthocyanin coloration. The question of whether anthocyanins can function as effective light screens to modulate photosynthesis in plants was addressed by comparing photosynthetic responses in reddish-purple pods with those in green pods of the ornamental leguminous tree Bauhinia variegata. For these comparisons the actinic radiation employed was either red radiation (RR) which was poorly absorbed by anthocyanin or blue-green radiation (BGR) which was strongly absorbed by anthocyanin. Photon yields of photosystem 2 (PS2) photochemistry and photochemical chlorophyll fluorescence quenching coefficients (qp), measured over a range of photon flux densities (PFD) up to 1200 µmol m-2 s-1 at 23 °C and at five temperatures from 8 to 28 °C at a PFD of 260 µmol m-2 s-1, were almost identical in green pods irradiated with either RR or BGR and in purple pods irradiated with RR. However, qp values remained much higher in purple pods irradiated with BGR, e.g., 0.80 in BGR versus 0.29 in RR at a PFD of 1200 µmol m-2 s-1 at 23 °C, and 0.67 in BGR versus 0.28 in RR at a PFD of 260 µmol m-2 s-1 at 8 °C. The higher values of qp in BGR compared to RR indicated that photoabatement by anthocyanin allowed the first stable acceptor of PS2, QA, to be kept in a more oxidized state, thus decreasing the likelihood of photoinhibition. This was confirmed by demonstrating a lower susceptibility to photoinhibition in purple pods than in green pods in the sunlight, either naturally in pods on trees or in detached pods exposed to photoinhibitory conditions. We conclude that photoabatement by anthocyanin is a mechanism for allowing maintenance of higher oxidative levels of PS2 acceptor during episodes of high radiation stress, thereby minimizing photodamage to photosynthetic tissues.
Keyword Plant Sciences
Chlorophyll Fluorescence
Radiation Colour
Q-Index Code C1

Document type: Journal Article
Sub-type: Article (original research)
Collection: School of Agriculture and Food Sciences
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Created: Wed, 11 Jun 2008, 00:55:53 EST