Premium
A test of the ‘one‐point method’ for estimating maximum carboxylation capacity from field‐measured, light‐saturated photosynthesis
Author(s) -
De Kauwe Martin G.,
Lin YanShih,
Wright Ian J.,
Medlyn Belinda E.,
Crous Kristine Y.,
Ellsworth David S.,
Maire Vincent,
Prentice I. Colin,
Atkin Owen K.,
Rogers Alistair,
Niinemets Ülo,
Serbin Shawn P.,
Meir Patrick,
Uddling Johan,
Togashi Henrique F.,
Tarvainen Lasse,
Weerasinghe Lasantha K.,
Evans Bradley J.,
Ishida F. Yoko,
Domingues Tomas F.
Publication year - 2016
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/nph.13815
Subject(s) - photosynthesis , mathematics , mean squared error , carboxylation , biosphere , irradiance , atmospheric sciences , statistics , botany , ecology , chemistry , physics , biology , biochemistry , quantum mechanics , catalysis
Summary Simulations of photosynthesis by terrestrial biosphere models typically need a specification of the maximum carboxylation rate ( V cmax ). Estimating this parameter using A – C i curves (net photosynthesis, A , vs intercellular CO 2 concentration, C i ) is laborious, which limits availability of V cmax data. However, many multispecies field datasets include net photosynthetic rate at saturating irradiance and at ambient atmospheric CO 2 concentration ( A sat ) measurements, from which V cmax can be extracted using a ‘one‐point method’. We used a global dataset of A – C i curves (564 species from 46 field sites, covering a range of plant functional types) to test the validity of an alternative approach to estimate V cmax from A sat via this ‘one‐point method’. If leaf respiration during the day ( R day ) is known exactly, V cmax can be estimated with an r 2 value of 0.98 and a root‐mean‐squared error ( RMSE ) of 8.19 μmol m −2 s −1 . However, R day typically must be estimated. Estimating R day as 1.5% of V cmax, we found that V cmax could be estimated with an r 2 of 0.95 and an RMSE of 17.1 μmol m −2 s −1 . The one‐point method provides a robust means to expand current databases of field‐measured V cmax , giving new potential to improve vegetation models and quantify the environmental drivers of V cmax variation.