AP BIOLOGY

Detailed explanation-1: -The vascular cambium is a layer of meristematic cells (or initials) that arises between primary xylem and phloem. Although it is a single layer of cells, in actual practice it is difficult to distinguish that layer from its immediate derivatives on either side. Hence, the term cambial zone is used (Fig.

Detailed explanation-2: -The cambium is defined as the actively dividing layer of cells that lies between, and gives rise to the secondary xylem and phloem.

Detailed explanation-3: -The tissues in woody stems, starting from the outer layer are: bark, vascular cambium, sapwood and heartwood (Figure 3.2. 1).

Detailed explanation-4: -The cambium present between primary xylem and primary phloem is called the intrafascicular cambium (within vascular bundles).

Detailed explanation-5: -The vascular cambium, which produces xylem and phloem cells, originates from procambium that has not completely differentiated during the formation of primary xylem and primary phloem.