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ARS Home » Pacific West Area » Davis, California » Crops Pathology and Genetics Research » Research » Research Project #435948

Research Project: Developing Solar-Induced Chlorophyll Fluorescence as a Ground-Based and Remotely-Sensed Physiological Indicator of Grapevine Stress

Location: Crops Pathology and Genetics Research

Project Number: 2032-21220-007-33-T
Project Type: Trust Fund Cooperative Agreement

Start Date: Apr 15, 2019
End Date: Apr 15, 2020

Objective:
1) In controlled conditions, compare active (traditional fluorescence sensors) and passive Solar-induced chlorophyll fluorescence (SIF) measurements at the leaf scale to validate signal output for new ground-based (tower) and remotely sensed (satellite) approaches for grapevines and vineyards. a. Compare responses of common grapevine varietals for drought, heat, and nutrient stressors. b. Combine results with current modelling efforts aimed at understanding how stress-induced changes in leaf structure impact signals gleaned from various sensor platforms. 2) Utilize existing experimental infrastructure (e.g. GRAPEX and other flux systems) to test SIF based physiological indicators from other methods.

Approach:
Investigate leaf structural and biophysical components in relation to light absorption within the leaf profile driving variation in photosynthetic rate under well-watered and water deficient conditions. Leaf-level performance will be scaled up to canopy-level productivity and linked via chlorophyll fluorescence(ChlF) measurements. conduct experiments under both controlled (potted plants subjected to drydown) and field conditions. Utilizing our standard leaf gas exchange, ChlF and water potential measurements on potted vines subjected to well-watered soil drydown conditions, while simultaneously capturing fluorescence and transmittance profiles in Vitis vinifera varieties. Leaves from these experiments will be measured and then immediately scanned with microCT. SIF will be retrieved from both top and bottom of leaves to relate to light absorption profiles. In order to get a comprehensive understanding of ChlF responses to environmental variables (i.e. soil water content, heat, light) at the field scale, we will monitor ChlF from passive and active techniques at the leaf and canopy level. Complementary pulse amplitude modulated (PAM) and spectrally resolved leaf fluorescence will be measured. Complementary PAM and spectrally resolved leaf fluorescence will be measured. Equipment will be deployed on experiments conducted as part of the Grape Remote sensing Atmospheric Profile & Evapotranspiration experiment (GRAPEX). Consequently, these observations will be run alongside canopy CO2, water vapor, energy, and momentum exchange from eddy covariance systems. As part of GRAPEX, detailed diurnal courses of leaf-level gas exchange and leaf and canopy spectral measurements are collected throughout the growing season.