Figure legends
Figure 1. In vivo absorbance spectra of epidermal anthocyanins. Measurements were performed on intact leaves in red and green individuals of the same genotype (Photinia × Fraseri “Red Robin” andParthenocissus quinquefolia ) or of different cultivars (red-leafed Ocimum basilicum cv. “Purple Ruffle” and cv. “Red Rubin” compared to green-leafed O. basilicum cv. “Tigullio”) using a spectrofluorimeter equipped with a double arm optical fibre bundle. Absorbance spectra were then calculated using the protocol of Agati, Cerovic, Pinelli, & Tattini (2011), by measuring the Chl fluorescence excitation over the 350-700 nm spectral region, for emission at 730 nm. Theoretical background: the Chl Fluorescence Excitation Ratio (ChlFER) of green to red leaves corresponds to the ratio of epidermal transmittance (EpT) and, hence, ChlFERgreen/red = EpTgreen/red. According to the Beer–Lambert’s law, A = −log T, thus log ChlFER is the difference in epidermal absorbance of red to green leaves: logChlFERgreen/red = EpAred − EpAgreen. Since fluorescence spectroscopy is a highly sensitive technique and fluorescence emitted by chlorophylls is intense, logChlFER is more accurate than reflectance spectroscopy in measuringin vivo absorbance of leaf epidermis, especially in the UV-blue waveband. In fact, reflectance is very low over the 350-480 nm waveband, due to high absorbance of both epidermal located phenylpropanoids and photosynthetic pigments located in the adaxial mesophyll layers.
Figure 2. Heat map showing differentially expressed genes, based on log2 fold change of transcript abundance of purple (‘Red Rubin’) to green (‘Tigullio’) Ocimum basilicum leaves grown for four weeks in full sunlight, as detailed in Tattini et al. (2017). List of annotated genes and encoded proteins: (JAC1 ) auxilin-like J-domain protein required for chloroplast accumulation response1; (FtsZ1 ) Filamenting Temperature-Sensitive Z1; (CAP10A ) Chlorophyll a-b binding protein CP2410A; (NIFU3 ) Nitrogen Fixation-like 3; (CURT1A ), CURVATURE THYLAKOID 1A; (FAR1 ) Far Red Impaired Response 1; (PTC52 ) Protochlorophyllide-aoxygenase; (ELIP2 ) early light-induced protein 2; (CLH1 ) Chlorophyllase 1; (NYC1 ) Non Yellow Coloring 1; (EX1 ), EXECUTER1; (PAP6 ) Plastid-Lipid-Associated 6; (PKS ) Phytochrome Kinase Substrate; (LNG ) LONGIFOLIA; (EXPA ) EXPANSIN; (ATHB ) DWARF27 ) β-carotene isomerase.
Figure 3. Response curves of net photosynthesis (A N) to changes in light irradiance (A N:PPFD curves) in reddish vs green cultivars. (A) Response curves of green (green symbols) and black (red symbols)Ophiopogon planiscapus ‘Nigrescens’ grown in sunlight (redrawn from Hatier, Clearwater, & Gould, 2013). (B) Response curves ofPhysocarpus amurensis ‘Maxim’ (green symbols) andPhysocarpus opulifolius ‘Diablo’ (red symbols) grown under natural sunlight (1000-1500 μmol quanta m-2 s-1 (redrawn from Zhang, Zhong, Wang, Sui, & Xu, 2016). (C) Response curves of Acer platanoides ‘Summer Shade’ (green symbols) and ‘Crimson King’ (red symbols) grown for three month in full sunlight (Fini, unpublished data). (D) Response curves of green (Tigullio, green symbols) and purple (Red Rubin, red symbols) Ocimum basilicum grown for four weeks in full sunlight (redrawn from Tattini et al. 2017).