Fig. 4.

Effects of NPA, an auxin transport inhibitor, on leaf vascular development and vein densities in G. gynandra and T. hassleriana. (A–D) G. gynandra and (E–H) T. hassleriana plants were grown in half-strength Kimura B nutrient solution without (A, C, E, and G) or with 20 μM NPA (B, D, F, and H). Vein patterns and cross-sections of the fifth newly developed leaves (2.5–3 cm long) are shown. (Scale bar: 100 μm.) (C, D, G, and H) MV: midvein (double arrows). (I and J) Vein density differences between control and NPA-treated leaves of G. gynandra (I) and T. hassleriana (J) (eight biological replicates each; Dataset S7). (K) The total vein density in the fifth mature leaves (eight biological replicates each). The statistical significance was determined by Student’s one-tailed t test (*P < 0.05; **P < 0.0005).