Taproot systems have a large, persistent major root, whereas fibrous root systems are shallow, branched, and shorter-lived. A root cap protects the tip as an apical meristem replaces cells lost during rapid extension. This last zone includes root hairs, epidermis, and the cortex. The cortex consists of hypodermis, storage parenchyma, and endodermis. Some roots are specialized for storage or adapted to low-oxygen environments.
Secondary tissues increase a tall plant's girth and enable plants to reach sunlight.
Two lateral meristems, vascular cambium and cork cambium, each produce secondary xylem and phloem to provide support. The vascular cambium forms a tree's wood, while cork cambium produces part of its bark. The McGraw-Hill Companies. Any use is subject to the Terms of Use and Privacy Policy .