Secondary Growth: Advantages and Risks

Abstract

Growth of gymnosperms and angiosperms (monocotyledons and dicotyledons) is based on the following stages. Primary meristems, i.e. derivates from embryonic tissue, induce longitudinal growth. This is called primary growth. At the tips of all branches and roots there is a primary meristem (apical meristem) (3.1-3.3). Behind the tip, some cells remain meristematic and form the lateral meristem. This is the vascular cambium that permits secondary growth and is responsible for stem thickening (3.4). Reactivated parenchyma cells in the cortex form the periderm. A meristem of secondary origin creates the periderm. It replaces the epidermis in stems and roots, which grow bigger by secondary growth.