Roots: a dynamic system -Root Epidermal and cortical cells lysed and invaded by bacteria Main sites of uptake of nutrients& water(根 Micro-organisms with m crobial and 毛区) plant mucilages Cells dividing spreading into the so or meristem expanding or elongation Sloughed root cap celis zne分生区 Root cap 与伸长区Roots: a dynamic system Main sites of uptake of nutrients & water（根 毛区） Cells dividing or meristem & expanding or elongation zone分生区 与伸长区