*2.4. Leaf Gas Exchange: Light Response Curves*

The 5th leaves from TE plants were placed in the chamber of a Li-COR 6400, which was fitted with a 2 cm × 3 cm red/blue LED Li-COR standard light source (88Red/12%Blue). The leaf temperature was set to 24 ◦C, with a relative humidity of 55–65% and a CO<sup>2</sup> level held at 800 µL L−<sup>1</sup> . Three leaves from separate plants under each treatment were used at 20, 54, and 134 DIT, corresponding with 5 December 2018, 8 January 2019, and 29 March 2019, respectively. Measurements were performed on cloudy days. Light curves began at a high light intensity and decreased gradually following the procedure from Lanoue et al. [29]. At each light level, the photosynthetic rate was allowed to reach a steady state; then, a measurement was taken for that light level. Photosynthetic rates were plotted against light intensity and fitted to a regression line following the equation y = y<sup>o</sup> + a(1−e (−b∗x)), using SigmaPlot 10.0 to determine the photosynthetic maximum. A linear regression (y = mx + b) using the photosynthetic rates at the light levels of 0–100 µmol m−<sup>2</sup> s <sup>−</sup><sup>1</sup> was used to calculate both the light compensation point (LCP) and quantum yield (QY).
