prokambium

Prokambium, also referred to as pro cambium or procambium in some texts, is a primary meristem in the apical region of vascular plants. It originates from provascular tissue during embryogenesis and its activity marks the formation of the primary vascular system. The procambium differentiates into primary xylem and primary phloem, establishing the conductive tissues that transport water, minerals, and organic nutrients in young shoots and roots. In the stem, procambial strands arise between the protoderm and ground meristem and, as development proceeds, differentiate into vascular bundles. In many dicots these bundles form a ring, whereas in many monocots they appear as scattered strands.

The term prokambium is frequently treated as synonymous with procambium, although some older usage resists narrowly defining it and uses it to denote the earliest provascular tissue that gives rise to both vascular tissues and related meristematic derivatives. Prokambial activity is limited to primary growth; secondary growth arises later from lateral meristems such as the cambium. The presence of prokambial tissue is a feature of seed plants and other vascular plants, enabling the establishment of their initial vascular architecture during embryogenesis and early plant development.