*2.2. Leaf Sample Collection and Area Determination*

Pea plants have compound leaves consisting of stipules, leaflets, petioles, rachis, and tendrils [25]. The pea cultivars used in this study were normal and semi-leafless leaf types. Normal leafed cultivars had a wide flat leaf lamina surface from stipules, leaflets, and relatively short petioles and rachis. Semi-leafless cultivars had stipules, a longer petiole and rachis, with more tendrils, but no leaflets. Unless otherwise stated, we refer to the flat leaf surface as 'lamina', and the petiole, rachis plus tendrils as 'petiole'. Fully expanded young leaf samples from the second or third main stem node, counting down from the apical tip, were sampled for chlorophyll, carotenoid, anthocyanin and wax measurements. Three leaf samples were collected from each plot and placed in plastic bags in an ice box cooler to avoid evaporative loss prior to transport to the laboratory. The leaf samples were collected twice during the pea growing season, at early flowering, and the full seed stages. Leaf samples were clipped at the main stem node, separated into lamina and petiole components, and then lamina and petiole scanned separately for each plot using winRHIZO (Regent Instruments Inc, Quebec City, Canada) to determine their respective projected surface areas (cm2). For each plot and time of collection, one leaf was used for chlorophyll and carotenoid extraction in acetone, another for anthocyanin in acidified ethanol, and the third leaf was used for wax extraction in chloroform.

#### *2.3. Chlorophyll and Carotenoid Determination*

Chlorophyll and carotenoid measurements were performed according to Lichtenthaler [26]. A 1.22 cm<sup>2</sup> stipule disc, and the entire petiole, using the same scanned tissue above, were each placed in 10 mL glass tubes with a tight cap, 3.5 mL of 100% acetone was added, and samples incubated for 6 h at room temperature for complete pigment extraction. Samples were then vortex mixed and centrifuged for 5 min at 5000 rpm. The supernatant was used for absorbance (A) measurement using an Agilent 8453 diode array spectrophotometer with 1.6 ± 0.5 nm resolution, equipped with Chem Station software for UV-visible spectroscopy (Agilent Technologies, Santa Clara, CA, USA), at wavelengths 470, 645, 662 and 710 nm. Concentrations of chlorophyll a, chlorophyll b, total chlorophyll, and total carotenoid were determined in μg cm−<sup>2</sup> using the following equations:

$$\text{Chlorophyll a (\(\mu\) mL}^{-1}) = \text{(11.24(A}\_{662} - A\_{710})\text{)} - \text{(2.04(A}\_{645} - A\_{710})\text{)}\tag{1}$$

$$\text{Chlorophyll b (\(\mu\) mL}^{-1}\text{)} = \text{(20.13(A}\_{645} - A\_{710})\text{)} - \text{(4.19(A}\_{662} - A\_{710})\text{)}\tag{2}$$

$$\text{Total Chloophyll (\mu g mL}^{-1}\text{)} = \text{(7.05(A}\_{662} - A\_{710})\text{)} + \text{(18.09(A}\_{645} - A\_{710})\text{)}\tag{3}$$

Total carotenoid (μg mL<sup>−</sup>1) = (1000(A470 <sup>−</sup> A710)) <sup>−</sup> (1.90 Chlorophyll a) <sup>−</sup> (63.14 Chlorophyll b) (4)

In order to present the data in μg cm−2, the results from the above equations were multiplied by the extraction volume (3.5 mL), and then divided by the sample (lamina or petiole) projected area (cm2).
