Describe5 marksChallenge
In a herbaceous dicotyledonous plant, the arrangement of vascular tissues differs between the stem and the root. In a transverse section of a young stem, vascular bundles are found in a ring near the periphery. Each bundle contains xylem and phloem. In a transverse section of a root, the vascular tissue forms a central cylinder with xylem and phloem arranged differently.
(a) Describe the distribution of xylem and phloem in a transverse section of a herbaceous dicot stem and of a herbaceous dicot root. (b) Describe how the structural features of xylem vessel elements, phloem sieve tube elements, and companion cells are adapted to their functions in transport.