title: Inherent limitations of nondestructive chlorophyll meters:  a comparison of two types of meters.
abstract: Two types of nondestructive chlorophyll meters were compared with a standard, destructive chlorophyll measurement technique.  The nondestructive chlorophyll meters were 1) a custom built, single-wavelength meter, and 2) the recently introduced, dual-wavelengh, chlorophyll meter from Minolta (model SPAD-502).  Data from both meters were closely correlated with destructive measurements of chlorophyll (r2 = 0.90 and 0.93; respectively) for leaves with chlorophyll concentrations ranging from 100 to 600 mg m-2, but both meters consistently overestimated chlorophyll outside this range.  Although the dual-wavelength meter was slightly more accurate than the single-wavelength meter (higher r2), the light-scattering properties of leaf cells and the nonhomogeneous distribution of chlorophyll in leaves appear to limit the ability of all meters to estimate in vivo chlorophyll concentration.
authors.affiliation: Plants, Soils, and Biometeorology Department, Utah State University, Logan 84322-4820.
authors.forename: O A
authors.initials: OA
authors.lastname: Monje
authors.forename: B
authors.initials: B
authors.lastname: Bugbee
mesh_terms: D002734:Chlorophyll / Q000032:analysis*; D003124:Colorimetry / Q000295:instrumentation; D005069:Evaluation Studies as Topic; D008027:Light; D012275:Oryza / Q000737:chemistry / Q000528:radiation effects; D018515:Plant Leaves / Q000737:chemistry* / Q000528:radiation effects; D013025:Glycine max / Q000737:chemistry / Q000528:radiation effects; D013057:Spectrum Analysis / Q000295:instrumentation; D014908:Triticum / Q000737:chemistry / Q000528:radiation effects
chemical_list: D002734:Chlorophyll