meristem

meristem , a specialized section of plant tissue characterized by cell division and growth. Much of the mature plant's growth is provided by meristems. Apical meristems found at the tips of stems and roots increase the length of these sections. Stems and roots may also grow in thickness or in diameter through cell divisions in lateral, or secondary, meristems, found just under the surface along the length of the stem or root. Tissues derived from differentiated lateral meristem are known as secondary tissues. In one type of lateral meristem, called cambium, or vascular cambium, the cells divide and differentiate to form the conducting tissues of the plant, i.e., the wood , or xylem, and the phloem (see bark ; stem ). The growth in diameter of tree trunks is wholly dependent on the division of cambium cells. Other meristematic tissues include cork cambium, which divides to produce waterproofing and protective cork tissue at the surface of the stem and root; and intercalary meristems, modified apical meristems found in different positions than either apical or lateral meristems, e.g., in the stem nodes of grasses. See also differentiation , in biology.

meristem A plant tissue consisting of actively dividing cells that give rise to cells that differentiate into new tissues of the plant. The most important meristems are those occurring at the tip of the shoot and root (see apical meristem) and the lateral meristems in the older parts of the plant (see cambium; cork cambium).

meristem A group of plant cells that are capable of dividing indefinitely and whose main function is the production of new growth. They are found at the growing tip of a root or a stem (apical meristem); in the cambium (lateral meristem); and, in grasses, also within the stem and leaf sheaths (intercalary meristem).