Photosynthetic light response curves determined with the leaf oxygen electrode: minimisation of errors and significance of the convexity term

Akhkha, A., Reid, I., Clarke, D.D. and Dominy, P. (2001) Photosynthetic light response curves determined with the leaf oxygen electrode: minimisation of errors and significance of the convexity term. Planta, 214(1), pp. 135-141. (doi:10.1007/s004250100599)

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Publisher's URL: http://dx.doi.org/10.1007/s004250100599

Abstract

From photosynthetic studies on a range of monocotyledonous (C-3 and C-4) and dicotyledonous (C-3) plants using a leaf oxygen electrode, we conclude the following. (i) A non-linear model [J.H.M.Thornley (1976) Mathematical models in plant physiology, Academic Press, London; B. Marshall and P.V. Biscoe (1980) J Exp Bot 31:29-39] significantly better describes the photosynthetic light response curve [rate of photosynthesis (P) versus incident photosynthetic photon flux density (I)] than the frequently used linear hyperbolic model [E.I. Rabinowich (1951) Photosynthesis and related processes, vol 2, Wiley, New York]. (ii) When used at the recommended CO2 partial pressures (Ca=1-5 kPa), CO2 supply saturates the photosynthesis rate in the C-3 dicot Phaseolus coccineus L. but not in the C-3 monocot Hordeum vulgare L.. (iii) Fits using a linear hyperbolic model for P versus I produce relatively large and statistically significant errors (,60%) in the estimation of Pmax and quantum efficiency (!) if Ca is not >5 kPa. (iv) The convexity term, Š, incorporated into the non-linear models for P versus I appears to reflect the limitation placed on the carboxylation processes by the supply of CO2 to the chloroplast stroma. Therefore, the use of a non-linear model providing an estimate of Š should be encouraged, as it is likely to provide information on the physiological status of plants.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Dominy, Dr Peter
Authors: Akhkha, A., Reid, I., Clarke, D.D., and Dominy, P.
Subjects:Q Science > QH Natural history > QH301 Biology
College/School:College of Medical Veterinary and Life Sciences > School of Life Sciences
Journal Name:Planta
ISSN:0032-0935
ISSN (Online):1432-2048

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