title: High-Throughput Phenotyping of Maize Leaf Physiological and Biochemical Traits Using Hyperspectral Reflectance.
abstract: High-throughput, noninvasive field phenotyping has revealed genetic variation in crop morphological, developmental, and agronomic traits, but rapid measurements of the underlying physiological and biochemical traits are needed to fully understand genetic variation in plant-environment interactions. This study tested the application of leaf hyperspectral reflectance (λ = 500-2,400 nm) as a high-throughput phenotyping approach for rapid and accurate assessment of leaf photosynthetic and biochemical traits in maize (Zea mays). Leaf traits were measured with standard wet-laboratory and gas-exchange approaches alongside measurements of leaf reflectance. Partial least-squares regression was used to develop a measure of leaf chlorophyll content, nitrogen content, sucrose content, specific leaf area, maximum rate of phosphoenolpyruvate carboxylation, [CO2]-saturated rate of photosynthesis, and leaf oxygen radical absorbance capacity from leaf reflectance spectra. Partial least-squares regression models accurately predicted five out of seven traits and were more accurate than previously used simple spectral indices for leaf chlorophyll, nitrogen content, and specific leaf area. Correlations among leaf traits and statistical inferences about differences among genotypes and treatments were similar for measured and modeled data. The hyperspectral reflectance approach to phenotyping was dramatically faster than traditional measurements, enabling over 1,000 rows to be phenotyped during midday hours over just 2 to 4 d, and offers a nondestructive method to accurately assess physiological and biochemical trait responses to environmental stress.
authors.affiliation: Carl R. Woese Institute for Genomic Biology (C.R.Y., T.T., C.M.M., Y.C., P.J.B., A.D.B.L., E.A.A.), Department of Plant Biology (C.M.M., A.D.B.L., E.A.A.), and Department of Crop Sciences (P.J.B.), University of Illinois at Urbana Champaign, Urbana, Illinois 61801.|Plant Protection Department, Fujian Agriculture and Forestry University, Fuzhou 350002, China (Y.C.).|Department of Molecular Genetics and Microbiology and Genetics Institute, University of Florida, Gainesville, Florida 32610 (A.M.M., L.M.M.); and.|Global Change and Photosynthesis Research Unit, United States Department of Agriculture-Agricultural Research Service, Urbana, Illinois 61801 (E.A.A.).
authors.forename: Craig R
authors.initials: CR
authors.lastname: Yendrek
authors.affiliation: Carl R. Woese Institute for Genomic Biology (C.R.Y., T.T., C.M.M., Y.C., P.J.B., A.D.B.L., E.A.A.), Department of Plant Biology (C.M.M., A.D.B.L., E.A.A.), and Department of Crop Sciences (P.J.B.), University of Illinois at Urbana Champaign, Urbana, Illinois 61801.|Plant Protection Department, Fujian Agriculture and Forestry University, Fuzhou 350002, China (Y.C.).|Department of Molecular Genetics and Microbiology and Genetics Institute, University of Florida, Gainesville, Florida 32610 (A.M.M., L.M.M.); and.|Global Change and Photosynthesis Research Unit, United States Department of Agriculture-Agricultural Research Service, Urbana, Illinois 61801 (E.A.A.).
authors.forename: Tiago
authors.initials: T
authors.lastname: Tomaz
authors.affiliation: Carl R. Woese Institute for Genomic Biology (C.R.Y., T.T., C.M.M., Y.C., P.J.B., A.D.B.L., E.A.A.), Department of Plant Biology (C.M.M., A.D.B.L., E.A.A.), and Department of Crop Sciences (P.J.B.), University of Illinois at Urbana Champaign, Urbana, Illinois 61801.|Plant Protection Department, Fujian Agriculture and Forestry University, Fuzhou 350002, China (Y.C.).|Department of Molecular Genetics and Microbiology and Genetics Institute, University of Florida, Gainesville, Florida 32610 (A.M.M., L.M.M.); and.|Global Change and Photosynthesis Research Unit, United States Department of Agriculture-Agricultural Research Service, Urbana, Illinois 61801 (E.A.A.).
authors.forename: Christopher M
authors.initials: CM
authors.lastname: Montes
authors.affiliation: Carl R. Woese Institute for Genomic Biology (C.R.Y., T.T., C.M.M., Y.C., P.J.B., A.D.B.L., E.A.A.), Department of Plant Biology (C.M.M., A.D.B.L., E.A.A.), and Department of Crop Sciences (P.J.B.), University of Illinois at Urbana Champaign, Urbana, Illinois 61801.|Plant Protection Department, Fujian Agriculture and Forestry University, Fuzhou 350002, China (Y.C.).|Department of Molecular Genetics and Microbiology and Genetics Institute, University of Florida, Gainesville, Florida 32610 (A.M.M., L.M.M.); and.|Global Change and Photosynthesis Research Unit, United States Department of Agriculture-Agricultural Research Service, Urbana, Illinois 61801 (E.A.A.).
authors.forename: Youyuan
authors.initials: Y
authors.lastname: Cao
authors.affiliation: Carl R. Woese Institute for Genomic Biology (C.R.Y., T.T., C.M.M., Y.C., P.J.B., A.D.B.L., E.A.A.), Department of Plant Biology (C.M.M., A.D.B.L., E.A.A.), and Department of Crop Sciences (P.J.B.), University of Illinois at Urbana Champaign, Urbana, Illinois 61801.|Plant Protection Department, Fujian Agriculture and Forestry University, Fuzhou 350002, China (Y.C.).|Department of Molecular Genetics and Microbiology and Genetics Institute, University of Florida, Gainesville, Florida 32610 (A.M.M., L.M.M.); and.|Global Change and Photosynthesis Research Unit, United States Department of Agriculture-Agricultural Research Service, Urbana, Illinois 61801 (E.A.A.).
authors.forename: Alison M
authors.initials: AM
authors.lastname: Morse
authors.affiliation: Carl R. Woese Institute for Genomic Biology (C.R.Y., T.T., C.M.M., Y.C., P.J.B., A.D.B.L., E.A.A.), Department of Plant Biology (C.M.M., A.D.B.L., E.A.A.), and Department of Crop Sciences (P.J.B.), University of Illinois at Urbana Champaign, Urbana, Illinois 61801.|Plant Protection Department, Fujian Agriculture and Forestry University, Fuzhou 350002, China (Y.C.).|Department of Molecular Genetics and Microbiology and Genetics Institute, University of Florida, Gainesville, Florida 32610 (A.M.M., L.M.M.); and.|Global Change and Photosynthesis Research Unit, United States Department of Agriculture-Agricultural Research Service, Urbana, Illinois 61801 (E.A.A.).
authors.forename: Patrick J
authors.initials: PJ
authors.lastname: Brown
authors.affiliation: Carl R. Woese Institute for Genomic Biology (C.R.Y., T.T., C.M.M., Y.C., P.J.B., A.D.B.L., E.A.A.), Department of Plant Biology (C.M.M., A.D.B.L., E.A.A.), and Department of Crop Sciences (P.J.B.), University of Illinois at Urbana Champaign, Urbana, Illinois 61801.|Plant Protection Department, Fujian Agriculture and Forestry University, Fuzhou 350002, China (Y.C.).|Department of Molecular Genetics and Microbiology and Genetics Institute, University of Florida, Gainesville, Florida 32610 (A.M.M., L.M.M.); and.|Global Change and Photosynthesis Research Unit, United States Department of Agriculture-Agricultural Research Service, Urbana, Illinois 61801 (E.A.A.).
authors.forename: Lauren M
authors.initials: LM
authors.lastname: McIntyre
authors.affiliation: Carl R. Woese Institute for Genomic Biology (C.R.Y., T.T., C.M.M., Y.C., P.J.B., A.D.B.L., E.A.A.), Department of Plant Biology (C.M.M., A.D.B.L., E.A.A.), and Department of Crop Sciences (P.J.B.), University of Illinois at Urbana Champaign, Urbana, Illinois 61801.|Plant Protection Department, Fujian Agriculture and Forestry University, Fuzhou 350002, China (Y.C.).|Department of Molecular Genetics and Microbiology and Genetics Institute, University of Florida, Gainesville, Florida 32610 (A.M.M., L.M.M.); and.|Global Change and Photosynthesis Research Unit, United States Department of Agriculture-Agricultural Research Service, Urbana, Illinois 61801 (E.A.A.).
authors.forename: Andrew D B
authors.initials: AD
authors.lastname: Leakey
authors.affiliation: Carl R. Woese Institute for Genomic Biology (C.R.Y., T.T., C.M.M., Y.C., P.J.B., A.D.B.L., E.A.A.), Department of Plant Biology (C.M.M., A.D.B.L., E.A.A.), and Department of Crop Sciences (P.J.B.), University of Illinois at Urbana Champaign, Urbana, Illinois 61801; lisa.ainsworth@ars.usda.gov.|Plant Protection Department, Fujian Agriculture and Forestry University, Fuzhou 350002, China (Y.C.); lisa.ainsworth@ars.usda.gov.|Department of Molecular Genetics and Microbiology and Genetics Institute, University of Florida, Gainesville, Florida 32610 (A.M.M., L.M.M.); and lisa.ainsworth@ars.usda.gov.|Global Change and Photosynthesis Research Unit, United States Department of Agriculture-Agricultural Research Service, Urbana, Illinois 61801 (E.A.A.) lisa.ainsworth@ars.usda.gov.
authors.forename: Elizabeth A
authors.identifier: 0000-0002-3199-8999
authors.initials: EA
authors.lastname: Ainsworth
mesh_terms: D002678:Chimera; D002734:Chlorophyll / Q000378:metabolism; D057166:High-Throughput Screening Assays / Q000379:methods; D016018:Least-Squares Analysis; D008954:Models, Biological; D009584:Nitrogen / Q000378:metabolism; D010641:Phenotype; D010788:Photosynthesis / Q000502:physiology; D018515:Plant Leaves / Q000737:chemistry / Q000502:physiology*; D003313:Zea mays / Q000235:genetics / Q000502:physiology*
chemical_list: D002734:Chlorophyll; D009584:Nitrogen