Relationships of leaf structural and anatomical traits
To complement the PCA, we further investigated the important
trait-to-trait comparisons. Across all the C4 grasses,
gm was positively related with leaf-level traits used to
estimate Kleaf, that is, IVD
(R 2 = 0.18, P = 0.07, Fig. 2a), leaf
thickness (R 2 = 0.45, P <0.01,
Fig. 2b) and average VED (R 2 = 0.44, P< 0.01, Fig. 2c), but negatively related with
Kleaf (R 2 = -0.28, P =
0.028, Fig. 2d). Similarly, Anet was positively related
with IVD (R 2 = 0.46, P = 0.01, Fig. 3a),
leaf thickness (R 2 = 0.15, P = 0.1, Fig.
3b) and average VED (R 2 = 0.22, P =
0.05, Fig. 3c), but negatively related with Kleaf(R 2 = -0.31, P = 0.016, Fig. 3d). In our
previous study on these C4 grasses (Pathare et
al ., 2020), we showed that gm scaled positively with
Smes (R 2 = 0.63, P< 0.001, Fig. S8a), SDada(R 2 = 0.47, P = 0.01, Fig. S8c), SR
(R 2 = 0.26, P = 0.04, Fig. S8d) and
Anet (R 2 = 0.26, P =
0.03, Fig. S8h), but showed no relationship with MCW,
SDaba and gsw (Fig. S8b,e and f).
Alternatively, Kleaf estimated using anatomical traits
in current study showed a significant negative relationship with all of
the above leaf-level structural and anatomical traits positively
associated with gm. Specifically, Kleafscaled negatively with Smes (R 2= -0.30, P = 0.027, Fig. 4a), SR (R 2 =
-0.50, P < 0.001, Fig. 4b) and SDada(R 2 = -0.38, P = 0.005, Fig. 4c).
Furthermore, traits associated with gm like Smes,
SDada and SR scaled positively with traits used to
estimate Kleaf like IVD, leaf thickness and VED (Fig. 1,
Table S4). We also investigated the relationships of gmand Kleaf with gmax,
gmax-ada and gmax-aba. Particularly,
gm showed a significant positive relationship with
gmax (R 2 = 0.30, P =
0.018, Fig. 5a) and gmax-ada(R 2 = 0.43, P < 0.01, Fig. 5b)
but did not relate with gmax-aba (Fig. S8g). Whereas,
Kleaf showed a significant negative relationship with
gmax-ada (R 2 = -0.27, P= 0.025, Fig. 5d) but did not relate with gmax and
gmax-aba.