3 Results
3.1 Patterns of ITV in
hypocotyl along latitudinal gradients
The first two PC axes (associated eigenvalues > 1)
accounted for 83.6% of the total variation among all these traits,
where the first axis (PC1) mainly reflected hypocotyl mass and size, and
the second axis was primarily determined by the shape index (RTD; Fig.
2). PC1 (fresh weight, fresh length, maximum transverse diameter, and
minimum transverse diameter) decreased significantly with increasing
latitudinal
gradients (R 2 = 0.42, P <
0.001). In addition, quadratic regression had a better explanation for
their relationship (R 2 = 0.53, P< 0.001; Fig. 3A). Intriguingly, RTD did not show any
significant correlation with latitude (P > 0.05;
Fig. 3B).