Figure legends
Figure 1. Relationship of mesophyll conductance (g m) with (a) interveinal distance (IVD), (b) leaf thickness and (c) average vein-to-epidermis distance (VED) for the 18 C4 grasses measured in current study. Numbers correspond to species listed in Table S1. Regression coefficient (R 2) is shown when P ≤ 0.001 (***),P ≤ 0.01 (**), P ≤ 0.05 (*) and P ≤ 0.1 (+). Points are mean values with n = 3-6 per species (Mean ± SE values are given in Pathare et al ., 2020 and Table S2).
Figure 2. Relationship of net photosynthetic rates (Anet) with (a) interveinal distance (IVD), (b) leaf thickness and (c) average vein-to-epidermis distance (VED) for the 18 C4 grasses measured in current study. Numbers correspond to species listed in Table S1. Regression coefficient (R 2) is shown when P ≤ 0.001 (***),P ≤ 0.01 (**), P ≤ 0.05 (*) and P ≤ 0.1 (+). Points are mean values with n = 3-6 per species (Mean ± SE values are given in Pathare et al ., 2020 and Table S2).
Figure 3. Relationship of adaxial stomatal density (SDada) with (a) interveinal distance (IVD), (b) leaf thickness and (c) average vein-to-epidermis distance (VED) for the 18 C4 grasses measured in current study. Numbers correspond to species listed in Table S1. Regression coefficient (R 2) is shown when P ≤ 0.001 (***),P ≤ 0.01 (**), P ≤ 0.05 (*) and P ≤ 0.1 (+). Points are mean values with n = 3-6 per species (Mean ± SE values are given in Pathare et al ., 2020 and Table S2).
Figure 4. Relationship of ratio of adaxial to abaxial stomatal density (stomatal ratio; SR) with (a) interveinal distance (IVD), (b) leaf thickness and (c) average vein-to-epidermis distance (VED) for the 18 C4 grasses measured in current study. Numbers correspond to species listed in Table S1. Regression coefficient (R 2) is shown when P ≤ 0.001 (***),P ≤ 0.01 (**), P ≤ 0.05 (*) and P ≤ 0.1 (+). Points are mean values with n = 3-6 per species (Mean ± SE values are given in Pathare et al ., 2020 and Table S2).
Figure 5. Relationship of mesophyll surface area exposed to intercellular air spaces (Smes) with (a) interveinal distance (IVD), (b) leaf thickness and (c) average vein-to-epidermis distance (VED) for the 18 C4 grasses measured in current study. Numbers correspond to species listed in Table S1. Regression coefficient (R 2) is shown when P ≤ 0.001 (***), P ≤ 0.01 (**), P ≤ 0.05 (*) and P ≤ 0.1 (+). Points are mean values with n = 3-6 per species (Mean ± SE values are given in Pathare et al ., 2020 and Table S2).
Figure 6. Principal component analysis biplot showing major axes of variation in important leaf-level physiological, structural and anatomical traits among18 diverse C4 grasses. Eigenvalues and factor loadings for first three principal components (PCs) are shown in Supporting Information Table S4. The arrows are the vectors showing the correlation (across the C4 grasses) between a trait and the PCs. The position of species in PC space is shown in blue circles. Points are mean values with n =3–6 per species (Mean ± SE values are given in Pathare et al ., 2020 and Table S2). Species names correspond to the description in Table S1. Total VLA, vein length per unit leaf area; BSias, BS exposed to intercellular air spaces; MAP, mean annual precipitation; MAT, mean annual temperature; BSCW, BS cell wall thickness; BS exposed to intercellular air spaces; BS area ratio (calculated as (BS area/ [BS area + Mesophyll area]); gm, mesophyll conductance to CO2diffusion estimated by Ogee et al . (2018); SDada, adaxial stomatal density; Smes, total mesophyll cell surface area exposed to intercellular air space per unit of leaf surface area; SR, stomatal ratio; Narea, leaf N content expressed on area basis; IVD, interveinal distance; VED, average vein-to-epidermis distance.
Figure 7. Relationship of (a) net photosynthetic rates (Anet), (b) instantaneous water-use efficiency (Anet/E) and (c) intrinsic water-use efficiency (Anet/gs) with principal component 1 (PC1, where higher score on PC1 indicates greater gm and lower Kleaf in drier habitats) for the 18 C4 grasses. Numbers correspond to species listed in Table S1. Regression coefficient (R 2) is shown when P ≤ 0.001 (***), P ≤ 0.01 (**), P ≤ 0.05 (*) and P ≤ 0.1 (+). Points are mean values with n = 3-6 per species (Mean ± SE values are given in Pathare et al ., 2020 and Table S2.