Plant Ground Tissue

Ground Tissue

Ground tissue, sometimes termed packing tissue, forms the bulk of primary plant tissue and occupies the areas that are not taken up by vascular tissue or cavities. It has a mechanical function, and may be concerned with storage or photosynthesis. Ground tissue typically consists of parenchyma, sclerenchyma or collen-chyma, and is often interspersed with idioblasts and secretory cells or canals. Ground tissue is initially formed at the apical meristems but may be supplemented by intercalary growth, and in monocots by tissues differentiated from primary and secondary thickening meristems. In dicots the ground tissue of secondary xylem (wood), formed by the vascular cambium, consists of fibres and axial parenchyma. In older stems the central area of ground tissue (pith) often breaks down, leaving a cavity (Fig. 2.2)