*3.2. Leaf Area, Specific Leaf Area, and Canopy Overlap Ratio*

Even though lettuce had a lower PCS than mizuna, its total leaf area was larger than that of mizuna at PPFDs <sup>≥</sup> <sup>125</sup> <sup>µ</sup>mol m−<sup>2</sup> s −1 (Figure 6A). This was due to the differences in leaf arrangement and morphology between the two species. The canopy overlap ratio of lettuce was higher than that of mizuna at PPFDs <sup>≥</sup> <sup>125</sup> <sup>µ</sup>mol m−<sup>2</sup> s −1 (Figure 6B), resulting in more intra-canopy shading in lettuce. With increasing PPFD, the differences in leaf area and canopy overlap ratio between the two species increased.

The SLA of lettuce was greater compared to mizuna, due to a larger total leaf area and lower shoot dry weight than mizuna at PPFDs <sup>≥</sup> <sup>125</sup> <sup>µ</sup>mol m−<sup>2</sup> s −1 (Figure 7B).
