Fig. 5
The first two axes of the PCA, which explain 24.6 and 17.1% of the variation in the data, respectively. Diploid parents and allotetraploid hybrids are largely overlapping, and the distinction between them can be attributed to SLA and WUE (5A). Individual species are also largely overlapping (5B), however the transgressive nature of the allotetraploid hybrids is evident as two of the diploid parents (B. rapa, B. oleracea,) occupy the center of variation whereas two of the allotetraploid hybrids (B. juncea, B. napus) explore the extremes of the variation evident in the data. Lf4_wetMg, the wet mass of the 4th leaf in mg; dry_shootsG, the mass of dried shoots in grams; Lf4_dryMg, the dry mass of the 4th leaf in mg; area_cm, the area of the 4th leaf in cm2; perimeter_cm, the perimeter of the 4th leaf in cm; dissection_index; the dissection index of the 4th leaf; SLA, specific leaf area of the 4th leaf; palisade_layers, the number of vertical layers of cells in the palisade parenchyma, palisade_max_depth, the maximum depth of palisade parenchyma in μM, palisade_min_depth, the minimum depth of the palisade parenchyma in μM; palisade_area, the area of palisade parenchyma in a 1000 μM long section of leaf in μM; spongy_max_depth, the maximum depth of spongy mesophyll in μM; spongy_min_depth, the minimum depth of spongy mesophyll in μM; spongy_area, the area of spongy mesophyll in a 1000 μM long section of leaf in μM, adaxial_max, the maximum depth of adaxial epidermis in μM, adaxial_min, the minimum depth of the adaxial epidermis in μM, adaxial_area, the area of adaxial epidermis in a 1000 μM long section of leaf in μM, abaxial_max, the maximum depth of the abaxial epidermis in μM; abaxial_min, the minimum depth of abaxial epidermis, abaxial_area, the area of the abaxial epidermis in a 1000 μM long section of leaf; palisade_spongy, the ratio of palisade parenchyma area to spongy mesophyll area; Photo, photosynthetic capacity (A max ); Cond, stomatal conductance (g s ); WUE, water use efficiency