Using foliar spectral properties to assess the effects of drought on plant water potential

Lorenzo Cotrozzi, John J. Couture, Jeannine M Cavender-Bares, Clayton C. Kingdon, Beth Fallon, George Pilz, Elisa Pellegrini, Cristina Nali, Philip A. Townsend

Research output: Contribution to journalArticlepeer-review

11 Scopus citations

Abstract

Drought frequency is predicted to increase in future environments. Leaf water potential (ΨLW) is commonly used to evaluate plant water status, but traditional measurements can be logistically difficult and require destructive sampling. We used reflectance spectroscopy to characterize variation in ΨLW of Quercus oleoides Schltdl. & Cham. under differential water availability and tested the ability to predict pre-dawn ΨLW (PDΨLW) using spectral data collected hours after pressure chamber measurements on dark-acclimated leaves. ΨLW was measured with a Scholander pressure chamber. Leaf reflectance was collected at one or both of two time points: immediately (ΨLW) and ~5 h after pressure chamber measurements (PDΨLW). Predictive models were constructed using partial least-squares regression. Model performance was evaluated using coefficient of determination (R2), root-mean-square error (RMSE), bias, and the percent RMSE of the data range (%RMSE). ΨLW and PDΨLW were well predicted using spectroscopic models and successfully estimated a wide variation in ΨLW (light- or dark-acclimated leaves) as well as PDΨLW (dark-acclimated leaves only). Mean ΨLW R2, RMSE and bias values were 0.65, 0.51 MPa and 0.09, respectively, with a %RMSE between 8% and 20%, while mean PDΨLW R2, RMSE and bias values were 0.60, 0.44 MPa and 0.01, respectively, with a %RMSE between 9% and 20%. Estimates of PDΨLW produced similar statistical outcomes when analyzing treatment effects on PDΨLW as those found using reference pressure chamber measurements. These findings highlight a promising approach to evaluate plant responses to environmental change by providing rapid measurements that can be used to estimate plant water status as well as demonstrating that spectroscopic measurements can be used as a surrogate for standard, reference measurements in a statistical framework.

Original languageEnglish (US)
Pages (from-to)1582-1591
Number of pages10
JournalTree physiology
Volume37
Issue number11
DOIs
StatePublished - Nov 1 2017

Bibliographical note

Funding Information:
67012-19900 supported J.J.C.; and NSF grant DEB-1342778/ 1342872 also supported P.A.T. and J.C.-B. Additional support from travel was provided by the College of Agriculture and Life Sciences at the University of Wisconsin-Madison and for quantitative data analyses through USDA W1S01599 to P.A.T.

Funding Information:
The authors wish to acknowledge the lifetime career of Dr George Pilz, his facilitation of and contribution to this research, and his dedication to teaching and mentoring generations of student at the University of Zamorano. George passed away after the present research was conducted. We would like to thank Tedward Erker and Esau Zuniga for assistance with fieldwork and Amy Charkowski, Paul Bethke and Curtis Frederick for access to osmolyte standards. This study was supported by funds from several sources. NSF grant IOS: 0843665 to J.C.-B. supported the design/establishment of the study site and associated travel. MIUR, Rome, project PRIN 2010–2011 ‘TreeCity’ and PRA 2015 project ‘Urban trees in the Global Change era’ supported L.C. for data analysis and manuscript writing; USDA NIFA AFRI Fellowship grant 2012-67012-19900 supported J.J.C.; and NSF grant DEB-1342778/ 1342872 also supported P.A.T. and J.C.-B. Additional support from travel was provided by the College of Agriculture and Life Sciences at the University of Wisconsin-Madison and for quantitative data analyses through USDA W1S01599 to P.A.T.

Funding Information:
This study was supported by funds from several sources. NSF grant IOS: 0843665 to J.C.-B. supported the design/establishment of the study site and associated travel. MIUR, Rome, project PRIN 2010–2011 ‘TreeCity’ and PRA 2015 project ‘Urban trees in the Global Change era’ supported L.C. for data analysis and manuscript writing; USDA NIFA AFRI Fellowship grant 2012-

Publisher Copyright:
© The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com

Keywords

  • Drought
  • Leaf water potential
  • Partial least-squares regression
  • Quercus oleoides
  • Reflectance spectroscopy
  • Water content

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