IMPORTANT DISTINCTION. “However, there are differences in the roles of hormones in plants and animals. For example, in animals, tissue morphogenesis often occurs through defined and invasive cell migration, whereas plant cells are immobilized due to rigid cell walls and thus have to rely on mobile signals to trigger comparable tissue reprogramming. In general, the synthesis of hormones in plants is not restricted to a particular, specialized tissue. Moreover, there is also extensive crosstalk between different hormonal and other signaling pathways that ultimately determine physiological outcomes.”
http://www.sciencedirect.com/science/article/pii/S009286740900258X