The young flowering plant shown on the left is constructed from three main types of organs : leaves,stems,and roots. Each plant organs in turn is made from three tissue systems: ground,dermai,and vascular.
All three tissue systems derive ultimately from the cell proliferative activity of the shoot or root apical meristems, and each contains a relatively small number of specialized cell types. These three common tissue systems, and the cells that comprise them, are described in this panel.
The three tissue systems
Cell division,growth,and differentiation give rise to tissue systems with specialized functions.
DERMAL TISSUE : the is the plant’s protective outer covering in contact with the environment. It facilitates water and ion uptake in roots and regulates gas exchange in leaves and stems.
VASCULAR TISSUE: together the phloem and the xylem form a continuous vascular system throughout the plant. This tissue conducts water and solutes between organs and also provides mechanical support.
GROUND TISSUE: this packing and supportive tissue accounts for much of the bulk of the young plant. It also functions in food manufacture and storage.