The plants of mtpin1 mtpin3 exhibit the constitutive shadeavoidance responses. (A) Mature compound leaf of 60-day-old wild-type (left) and mtpin1-1 mtpin3-1 (right). (B,C) A dissected branch of wild-type (B) and mtpin1-1 mtpin3-1 (C). Arrows point to the petioles and lines show the internodes. (D) The length of petiole on the different nodes in 60-day-old wild-type (WT) and mtpin1-1 mtpin3-1. (E) The length of internode in wild-type and mtpin1-1 mtpin3-1. (F) The chlorophyll content in wild-type and mtpin1-1 mtpin3-1. (G,H) Expression levels of MtIAA19, MtIAA29, and MtHB2 at petiole and internode in wild-type and mtpin1-1 mtpin3-1. * p < 0.05, ** p < 0.01, *** p < 0.001.