My research goal is to understand how phytohormones induce and regulate the differentiation, regeneration and evolution of vascular systems in plants. The research addresses fundamental issues of plant hormone biology: hormone production, transport pathways and hormonal mechanisms that control the differentiation of various cell types in the xylem and phloem of organized tissues, tumors and galls; providing practical tools for improving fiber and wood quality in forest trees and other industrial plants. Our study on tumors of plants led to the discovery of the role of the ethylene hormone in tumors; promoting the use of ethylene insensitive plants that are healthy and tumor free. My research and the entire field of vascular differentiation were recently summarized and discussed in the Springer’s book: Vascular Differentiation and Plant Hormones (2020).