Staff Publications

Staff Publications

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    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

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Record number 536751
Title The energy budget in C4 photosynthesis : insights from a cell-type-specific electron transport model
Author(s) Yin, Xinyou; Struik, Paul C.
Source New Phytologist 218 (2018)3. - ISSN 0028-646X - p. 986 - 998.
Department(s) Crop Physiology
Publication type Refereed Article in a scientific journal
Publication year 2018
Keyword(s) bioenergetics - C modelling - C photosynthesis - cell type - cyclic electron transport - energy balance - mixed decarboxylation - quantum yield
Abstract Extra ATP required in C4 photosynthesis for the CO2-concentrating mechanism probably comes from cyclic electron transport (CET). As metabolic ATP : NADPH requirements in mesophyll (M) and bundle-sheath (BS) cells differ among C4 subtypes, the subtypes may differ in the extent to which CET operates in these cells. We present an analytical model for cell-type-specific CET and linear electron transport. Modelled NADPH and ATP production were compared with requirements. For malic-enzyme (ME) subtypes, c. 50% of electron flux is CET, occurring predominantly in BS cells for standard NADP-ME species, but in a ratio of c. 6 : 4 in BS : M cells for NAD-ME species. Some C4 acids follow a secondary decarboxylation route, which is obligatory, in the form of ‘aspartate-malate’, for the NADP-ME subtype, but facultative, in the form of phosphoenolpyruvate-carboxykinase (PEP-CK), for the NAD-ME subtype. The percentage for secondary decarboxylation is c. 25% and that for 3-phosphoglycerate reduction in BS cells is c. 40%; but these values vary with species. The ‘pure’ PEP-CK type is unrealistic because its is impossible to fulfil ATP : NADPH requirements in BS cells. The standard PEP-CK subtype requires negligible CET, and thus has the highest intrinsic quantum yields and deserves further studies in the context of improving canopy productivity.
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