Assessing foliar chlorophyll contents with the SPAD-502 chlorophyll meter: a calibration test with thirteen tree species of tropical rainforest in French Guiana
INRA – Unité Mixte de Recherche Écologie des Forêts de Guyane,
2 CNRS – Unité Mixte de Recherche Écologie des Forêts de Guyane, Kourou, France
3 AgroParisTech-ENGREF- Unité Mixte de Recherche Écologie des Forêts de Guyane, Kourou, France
4 Harvard University, Department of Organismic and Evolutionary Biology, Harvard University Herbaria, 22 Divinity Avenue Cambridge, MA, 02138, USA
5 University of Gothenburg, Department of Plant and Environmental Sciences, Göteborg, Sweden
6 Université des Antilles et de la Guyane, Unité Mixte de Recherche Ecologie des Forêts de Guyane, Kourou, France
* Corresponding author: email@example.com
Accepted: 21 December 2009
• Chlorophyll meters such as the SPAD-502 offer a simple, inexpensive and rapid method to estimate foliar chlorophyll content. However, values provided by SPAD-502 are unitless and require empirical calibrations between SPAD units and extracted chlorophyll values.
• Leaves of 13 tree species from the tropical rain forest in French Guiana were sampled to select the most appropriate calibration model among the often-used linear, polynomial and exponential models, in addition to a novel homographic model that has a natural asymptote.
• The homographic model best accurately predicted total chlorophyll content (μg cm−2) from SPAD units (R2 = 0.89). Interspecific differences in the homographic model parameters explain less than 7% of the variation in chlorophyll content in our data set.
• The utility of the general homographic model for a variety of research and management applications clearly outweighs the slight loss of model accuracy due to the abandon of the species’ effect.
Key words: chlorophyll estimate / model calibration / homographic functions / neotropical trees
© INRA, EDP Sciences, 2010