Figure 3.

Analysis of Leaf Growth Allometry.

Ink spots were introduced on the surface of young leaves (pictures on the left in [A], [C], [E], and [G]) of N. tabacum ([A] and [B]), D. indica ([C] and [D]), H. rosa-sinensis ([E] and [F]), and S. jambos ([G] and [H]) and tracked until maturity (pictures on the right) (also see Supplemental Figure 1). For N. tabacum, D. indica, and H. rosa-sinensis, lengths of the distal (x) and the proximal (y) halves were measured at regular intervals, and the (x, y) values were plotted on double logarithmic scale ([B], [D], and [F], respectively) and fitted to the equation y = bx^α to determine the value of growth ratio (α). The actual values of x and y during growth are represented by triangles, while circles represent the theoretical values of x and y had the growth been isometric. For S. jambos, which showed bidirectional growth pattern ([G] and [H]), similar analysis of growth allometry was performed for the distal half (red line in [G]) and the proximal half (yellow line in [G]) separately. In the young S. jambos leaf (56 mm long), centers of the distal and the proximal halves are shown by the red and the yellow arrowheads, respectively. x_D and y_D represent the distal and the proximal parts of the distal half, respectively; x_P and y_P represent the same in the proximal half (G). The same points are marked in the mature (175 mm long) leaf. Plotting the values of x_D and y_D on the log scale shows that the distal part of the leaf grows with positive allometry (α_Distal = 2.3), while the proximal half of the leaf grows with negative allometry (α_Proximal = 0.73) (H). Closed circles indicate the actual values of x_D and y_D and closed triangles those of x_P and y_P during growth; theoretical values of x_D, y_D, and x_P, y_P for isometric growth are represented by open circles and triangles, respectively.