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The water-water cycle in leaves is not a major alternative electron sink for dissipation of excess excitation energy when CO<inf>2</inf> assimilation is restricted

Driever, SM and Baker, NR (2011) 'The water-water cycle in leaves is not a major alternative electron sink for dissipation of excess excitation energy when CO<inf>2</inf> assimilation is restricted.' Plant, Cell and Environment, 34 (5). 837 - 846. ISSN 0140-7791

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Abstract

Electron flux from water via photosystem II (PSII) and PSI to oxygen (water-water cycle) may provide a mechanism for dissipation of excess excitation energy in leaves when CO2 assimilation is restricted. Mass spectrometry was used to measure O2 uptake and evolution together with CO2 uptake in leaves of French bean and maize at CO2 concentrations saturating for photosynthesis and the CO2 compensation point. In French bean at high CO2 and low O2 concentrations no significant water-water cycle activity was observed. At the CO2 compensation point and 3% O2 a low rate of water-water cycle activity was observed, which accounted for 30% of the linear electron flux from water. In maize leaves negligible water-water cycle activity was detected at the compensation point. During induction of photosynthesis in maize linear electron flux was considerably greater than CO2 assimilation, but no significant water-water cycle activity was detected. Miscanthus×giganteus grown at chilling temperature also exhibited rates of linear electron transport considerably in excess of CO2 assimilation; however, no significant water-water cycle activity was detected. Clearly the water-water cycle can operate in leaves under some conditions, but it does not act as a major sink for excess excitation energy when CO2 assimilation is restricted. © 2011 Blackwell Publishing Ltd.

Item Type: Article
Subjects: Q Science > QH Natural history > QH301 Biology
Divisions: Faculty of Science and Health > Life Sciences, School of
Depositing User: Jim Jamieson
Date Deposited: 16 Sep 2011 09:03
Last Modified: 21 Oct 2019 10:15
URI: http://repository.essex.ac.uk/id/eprint/677

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