Fig. 1: Spectral characteristics of several shade plants, Acanthaceae plants, and Arabidopsis thaliana.

a Low-temperature (77-K) fluorescence emission spectra of Arabidopsis thaliana (At), three understory traditional Chinese medicine plants (P. ginseng, P. notoginseng and D. nobile) and two houseplants (E. aureum and F. albivenis [Fa]). b Wavelength of maximum fluorescence emission (λ_max) of the plant species from (a) Error bars (standard deviation) were calculated from three different experimental units (n = 3 independent experiments), and data were presented as mean values ± SD. c The absorption spectra of leaves from At, Ea and Fa. The absorption spectra were normalized to the maximum in the red region, which was set to 1. The differential absorption spectrum between Fa and At is shown as a dashed line. d, e 77-K fluorescence emission spectra of chloroplast (d) and thylakoid membranes (e) from Arabidopsis and Fa. f Absorption spectra at room temperature of At thylakoids and Fa thylakoids. The differential absorption spectrum between Fa thylakoids and At thylakoids (multiplied by 5) is shown as a dashed line, with peaks at 456.5 nm, 488.5 nm, 650 nm, and 693.5 nm and the shoulder at 718 nm indicated by arrows. g 77-K fluorescence emission spectra of the ten Acanthaceae plants Fa, S. cusia, J. brandegeeana, P. curviflorus, B. cristata, R. tuberosa, C. infundibuliformis, H. phyllostachya, A. squarrosa and A. paniculata. h Wavelength of maximum fluorescence emission for plants shown in g Error bars (standard deviation) were calculated from three different experimental units (n = 3 independent experiments), and data were presented as mean values ± SD. The fluorescence emission spectra were collected following excitation at 440 nm and normalized with respect to their wavelength at maximal emission in the far-red region (750 nm), which was set to 1. The data are based on three independent experiments, each producing similar results.