Effects and mechanism of mineral nutrient and phytohormone on root hair development A STUDY ON THE DEVELOPMENT AND ULTRASTRUCTURE OF MULTICELLULAR ROOT HAIR OF KALANCHOE FEDTSCHENKOI Characterization of Programmed Cell Death During the Senescence of Root Hairs in Arabidopsis Proliferation of Root Hairs and Formation of Transfer Cells of Root Out-Layers in Albizia julibrissin Induced by Rhizobia