Figure 4.

The inhibition of PDE activity promotes adventitious root development. A, Explants were treated with different concentrations of the PDE inhibitor sildenafil citrate, and root number per explant was determined after 5 d of treatment. B, Root number was also determined in explants treated with 10 μm IAA, 10 μm SNP, or 1 mg mL^–1 sildenafil citrate or in combined treatments. Root number values are expressed as mean ± se (n = 10 explants from at least three independent experiments). Bars with different letters are significantly different with P < 0.05 (t test).