Cambium

Cambium [ Botany ]

Dictionary of botanic terminology - index of names


	Cambium is a specialized tissues formed by a thin layer of dividing meristematic cell that form new tissues and causes the thickening of trunk and branches in plants.

Vascular cambium: a thin layer of dividing cells (lateral meristem) found between the wood and the bark of vascular plants. The cambium produces secondary xylem (wood) to the inside and secondary phloem and bark to the outside. At the same time, new cambium is produced. it causes the stem to increase in thickness, as indicated by its annual rings when wood is cut into a cross section. Cork cambium: As the vascular cambium produces new xylem and phloem, that causes the stem to expand. The cork cambium creates a new covering of cork for the plant called the periderm. Cork cells are filled with suberin and waxes, making a layer that is impermeable to air and water. These cells are dead at maturity. Phelloderm is produced to the inside of the cork cambium. These are live parenchyma cells at maturity.

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Holdfast roots [ Botany ]
Dictionary of botanic terminology - index of names

Some species of climbing plants develop holdfast roots which help to support the vines on trees, walls, and rocks. By forcing their way into minute pores and crevices, they hold the plant firmly in place.

Climbing plants, like the poison ivy (Toxicodendron radicans), Boston ivy (Parthenocissus tricuspidata), and trumpet creeper (Campsis radicans), develop holdfast roots which help to support the vines on trees, walls, and rocks. By forcing their way into minute pores and crevices, they hold the plant firmly in place. Usually the Holdfast roots die at the end of the first season, but in some species they are perennial. In the tropics some of the large climbing plants have hold-fast roots by which they attach themselves, and long, cord-like roots that extend downward through the air and may lengthen and branch for several years until they strike the soil and become absorbent roots.

Major references and further lectures:
1) E. N. Transeau “General Botany” Discovery Publishing House, 1994