Spectral reflectance indices and pigment functions during leaf ontogenesis in six subtropical landscape plants

Abstract

Pigment combinations are regulated during leaf ontogenesis. To better understand pigment function, alterations in chlorophyll, carotenoid and anthocyanin concentrations were investigated during different leaf development stages in six subtropical landscape plants, namely Ixora chinensis Lam, Camellia japonica Linn, Eugenia oleina Wight, Mangifera indica L., Osmanthus fragrans Lowr and Saraca dives Pierre. High concentrations of anthocyanin were associated with reduced chlorophyll in juvenile leaves. As leaves developed, the photosynthetic pigments (chlorophyll and carotenoid) of all six species increased while anthocyanin concentration declined.Chlorophyll fluorescence imaging of U PSII (effective quantum yield of PSII) and of NPQ (non-photochemical fluorescence quenching) and determination of electron transport rate-rapid light curve (RLC) showed that maximum ETR (leaf electron transport rate), U PSII and the saturation point in RLC increased during leaf development but declined as they aged. Juvenile leaves displayed higher values of NPQ and Car/Chl ratios than leaves at other developmental stages. Leaf reflectance spectra (400-800 nm) were measured to provide an in vivo non-destructive assessment of pigments in leaves during ontogenesis. Four reflectance indices, related to pigment characters, were compared with data obtained quantitatively from biochemical analysis. The results showed that the ARI (anthocyanin reflectance index) was linearly correlated to anthocyanin concentration in juvenile leaves, while a positive correlation of Chl NDI (chlorophyll normalized difference vegetation index) to chlorophyll a concentration was species dependent. Photosynthetic reflectance index was not closely related to Car/Chl ratio, while a structural-independent pigment index was not greatly altered by leaf development or species. Accordingly, it is suggested that the high concentration of anthocyanin, higher NPQ and Car/Chl ratio in juvenile leaves are important functional responses to cope with high radiation when the photosynthetic apparatus is not fully developed. Another two leaf reflectance indices, ARI and Chl NDI, are valuable for in vivo pigment evaluation during leaf development.

Light acclimation and HSO3 − damage on photosynthetic apparatus of three subtropical forest species

“…4 Images of chlorophyll fluorescence parameters (U PSII , NPQ/4 and qP) in P. massoniana (a), S. superba (b) and A. acuminatissima (c) leaf sections after long term light (100 and 12% sunlight) treatments and following shortterm treatments with 50 mM NaHSO 3 solution. Bar along the bottom of images indicates relative value of each parameter as a percentage environment (White and Critchley 1999;Schreiber 2004;Liu et al 2009). In the present study, RLCs were reliant on long-term different natural light intensities and showed distinctions with each other (Figs.…”

Lipidomics Analysis Reveals the Effect of Light Intensity on Lipid Metabolism and Leaf Color in Light-Sensitive Albino Tea Plant (Camellia Sinensis cv. Baijiguan)

“…Baijiguan is more sensitive to high light intensity, of which chloroplast development is retarded, and its chlorophyll content is lower than other green-leaf varieties at the same developmental stage [7]. Chlorophyll plays an essential role in photosynthesis by absorbing and transferring the light energy to other molecules of the photosynthetic electron transport chain [35]. The chlorophyll accumulation in plants is dynamic [36,37], which is a comprehensive process of synthesis and decomposition.…”

Location of Sampling Points in Optical Reflectance Measurements of Chinese Cabbage and Kale Leaves

“…To measure the wavelengths individually or simultaneously, optical meters were attached between the leaf mid-vein and edge parts, with the upper leaf pointing upward, as described by Davenport et al (2005). Reflectance spectra were recorded for the upper surfaces of the leaves, inter-veinal areas, or middle parts of the uppermost fully expanded leaves (Wang et al, 2004;Follett et al, 1992;Gitelson et al, 1996;Liu et al, 2009). However, most sampling locations in spectral reflectance measurements described in the literature were selected based on the suggestions in previous works.…”