In this article we will discuss about the definition and cell types of xylem tissue in plants. Definition of Xylem: Xylem can be defined as a complex tissue that is composed of four basic types of cell (tracheids, trachea, and xylem fibre and xylem parenchyma), remains in close association with phloem and has specialized functions like conduction of water and [...]
Phloem consists of sieve cell, sieve tube, companion cell, phloem parenchyma and fibre. 1. Sieve Cell-Origin: The mother cells of sieve cells vary in shape. They are slender, short cylindrical to elongate with both ends tapering. Numerous primary pit fields occur on lateral walls. During differentiation the mother cells elongate. Vacuole appears in the cytoplasm that streams actively. The cell [...]
In this article we will discuss about:- 1. Origin and Development of Vessel 2. Phylogeny of Vessel. Origin and Development of Vessel: Trachea (or vessel) originates from meristematic cells (Fig. 10.4) that are grouped together in a longitudinal file. The meristematic cells are known as xylem mother cell that develops from procambial cells in the primary xylem. In secondary xylem [...]