Technical Note: Handheld near Infared Spectroscopy for the Prediction of Leaf Physiological Status in Tree Seedlings

Abstract

Near infrared spectra obtained from leaf surfaces of Eucalyptus grandis seedlings were calibrated against physiological measurements of plant water stress, namely: relative water content, leaf water potential and stomatal conductance. In a controlled environment facility, spectral data were obtained from both abaxial and adaxial leaf surfaces as well as upper and lower leaves in the stem. The strongest coefficients of determination using cross-validation were r 2 CV = 0.85 for relative water content, r 2 CV = 0.74 for leaf water potential and r 2 CV = 0.80 for stomatal conductance. The use of a portable NIR instrument enabled the rapid assessment of physiological status of seedlings and would enable in situ, non-destructive, high-throughput monitoring of drought and recovery in the field. This would be particularly useful for non-destructive measurement in longitudinal studies.

Application of Infrared and Raman Spectroscopy for the Identification of Disease Resistant Trees

“…There are many commercial options available for high-throughput screening and/or phenotyping using portable and handheld NIR spectrometers, some of which come equipped with interchangeable accessories, like fiber-optic probes (Foley et al, 1998 ; Sorak et al, 2012 ; Warburton et al, 2014 ). While NIR spectrometers may be less sensitive and accurate than FT-IR spectrometers and Raman spectrometers (see below), ease of use and generally lower costs for NIR sample analysis make it an ideal tool for rapidly screening trees for disease resistance (Lupoi et al, 2014 ).…”

Non‐destructive assessment of grapevine water status in the field using a portable NIR spectrophotometer

“…The use of portable NIR spectroscopy for the assessment of plant water status has not been extensively addressed. Likewise, prediction of classical Ψ and RWC based on NIR spectroscopy has been reported for several crops, such as olive tree, Eucalyptus seedling and grapevine . Hence, there is considerable scope for improvement in the implementation of new, non‐invasive, fast and robust portable NIR equipment to in‐field assessing plant water status, as many features, such as the atmospheric conditions, the species, genotype, plant age, among others, affect conventional plant water status indicators, and potentially the NIR response also.…”

Assessing Trees, Wood and Derived Products with near Infrared Spectroscopy: Hints and Tips

“…Foliar spectroscopy is increasingly being used to determine hybridisation, foliar nutrition and even leaf physiology in the field. [33][34][35] This too presents issues of spectral acquisition. It is important to avoid stray light and so a standardised backing plate behind the leaf while it is being scanned is suggested (transflection mode).…”