Morphology of transformed walnut shoots. A) In vitro-grown plants of co-transformed 33-3-1. B) Untransformed control. Co-transformed plants had stunted growth, shorter internode lengths, and darker green, smaller, and more wrinkled leaves than the control. C) In vitro-grown plants of single-vector transformed line 29-3-1 were phenotypically similar to the untransformed control.