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apical meristema region of dividing tissue at the growing tips of roots and shoots that is responsible for increase in length of the plant body. MERISTEM cells are small, with thin walls and CYTOPLASM containing few vacuoles. They undergo active MITOSIS when growth is occurring (depending on the season) and the new cells look similar to the parental ones but become more vacuolated and elongated. Eventually, further away from the meristem, the cells undergo the process of CELL DIFFERENTIATION, taking on the appearance of mature plant cells.
Meristematic tissues are delicate and in need of protection. In shoots the apices are covered by tiny leaves forming apical buds at the tips of the branches and axillary buds at the nodes where the leaves join the stem. Root structures are less complex, each root-tip meristem being protected by a shield of loose cells called a ROOT CAP. Compare CAMBIUM.