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).