Assessing leaf pigment content and activity with a reflectometer

Abstract

This study explored reflectance indices sampled with a ' leaf reflectometer ' as measures of pigment content for leaves of contrasting light history, developmental stage and functional type (herbaceous annual versus sclerophyllous evergreen). We employed three reflectance indices : a modified normalized difference vegetation index (NDVI), an index of chlorophyll content ; the red\green reflectance ratio (R RED : R GREEN ), an index of anthocyanin content ; and the change in photochemical reflectance index upon dark-light conversions (∆PRI), an index of xanthophyll cycle pigment activity. In Helianthus annuus (sunflower), xanthophyll cycle pigment amounts were linearly related to growth light environment ; leaves in full sun contained approximately twice the amount of xanthophyll cycle pigments as leaves in deep shade, and at midday a larger proportion of these pigments were in the photoprotective, de-epoxidized forms relative to shade leaves. Reflectance indices also revealed contrasting patterns of pigment development in leaves of contrasting structural types (annual versus evergreen). In H. annuus sun leaves, there was a remarkably rapid increase in amounts of both chlorophyll and xanthophyll cycle pigments along a leaf developmental sequence. This pattern contrasted with that of Quercus agrifolia (coast live oak, a sclerophyllous evergreen), which exhibited a gradual development of both chlorophyll and xanthophyll cycle pigments along with a pronounced peak of anthocyanin pigment content in newly expanding leaves. These temporal patterns of pigment development in Q. agrifolia leaves suggest that anthocyanins and xanthophyll cycle pigments serve complementary photoprotective roles during early leaf development. The results illustrate the use of reflectance indices for distinguishing divergent patterns of pigment activity in leaves of contrasting light history and functional type.

The use of remote sensing in light use efficiency based models of gross primary production: A review of current status and future requirements

“…These changes manifest in two narrow waveband absorption features at 505 and at 531 nm and can be quantified using SVIs, such as the Photochemical Reflectance Index (PRI), defined as (Gamon et al, 1990), 570 531 570 531 PRI (5) comparing the reflectance at 531 nm ( 531 ) to a xanthophyll-insensitive reference band at 570nm ( 570 ). Originally established for sunflower leaves, the empirical relationship between PRI and has been confirmed over a wide range of species (Peñuelas et al, 1994;Filella et al, 1996;Gamon and Surfus, 1999) thereby demonstrating the potential use of this method for global estimation of . Upscaling of these findings from leaf to canopy, regional and global levels, however remains challenging.…”

Separating physiologically and directionally induced changes in PRI using BRDF models

“…These pigment changes manifest in a narrow waveband (difference) absorption feature centered at 531 nm (Gamon et al, 1993) and hence can be quantified on leaves, canopies and stands as the Photochemical Reflectance Index (PRI), (Gamon et al, 1992, 1993, Peñuelas et al, 1995, comparing the reflectance at 531 nm ( 531 ) to a xanthophyll-insensitive reference band at 570nm ( 570 ). Originally established for sunflower leaves, the empirical relationship between PRI and has been confirmed over a wide range of species (Peñuelas et al, 1994, Filella et al, 1997, Gamon and Surfus, 1999. Generalization of this 12 correlation for application at the stand level and beyond, however, remains difficult (Barton and North, 2001, Rahman et al 2001 as PRI is highly sensitive to viewangle, soil background reflectance, leaf angle distribution (at larger view angles) and leaf area (Barton and North, 2001).…”

Connection of the Photochemical Reflectance Index (PRI) with the Photosystem II Quantum Yield and Nonphotochemical Quenching Can Be Dependent on Variations of Photosynthetic Parameters among Investigated Plants: A Meta-Analysis

“…2018, 10, 771 2 of 25 -a photochemical reflectance index (PRI), which shows changes in the xanthophyll cycle [26]; -a normalized difference vegetation index (NDVI) [27], an optimized soil-adjusted vegetation index (OSAVI) [28], and an enhanced vegetation index (EVI) [29,30], which quantitatively show a photosynthesizing biomass; -a chlorophyll index (CI), which shows chlorophyll content in leaves [31,32]; and -a structural independent pigment index (SIPI), which is connected to the ratio of carotenoids to chlorophylls [33].…”