AP BIOLOGY

Detailed explanation-1: -The secondary growth of plants increase in stem thickness and it is due to the activity of the lateral meristems, which are absent in herbs or herbaceous plants. There are two types of lateral tissues involved in secondary growth, namely, vascular cambium and cork cambium.

Detailed explanation-2: -Primary growth is controlled by root apical meristems or shoot apical meristems, while secondary growth is controlled by the two lateral meristems, called the vascular cambium and the cork cambium.

Detailed explanation-3: -Secondary Growth There are two types of meristem in the plant stem: apical and lateral. As we just reviewed, primary growth occurs at the apical meristem and increases plant stem length. Secondary growth is growth at the lateral meristem and increases the girth of the stem.

Detailed explanation-4: -Secondary, or lateral, meristems, which are found in all woody plants and in some herbaceous ones, consist of the vascular cambium and the cork cambium. They produce secondary tissues from a ring of vascular cambium in stems and roots.

Detailed explanation-5: -Cork cambium cells produce a progressively thickening layer of cork, which contributes to the bark of a plant. These cells add girth to the plant stem, resulting in the thickening of the trunk (lateral growth)