Cambiais

Cambiais is the plural form of cambial, used in Portuguese-language botany to refer to cambial tissues in plants. Cambia are meristematic tissues responsible for secondary growth, producing new vascular tissue and contributing to the thickening of stems and roots in many vascular plants.

There are two primary cambial systems. The vascular cambium lies between the xylem and phloem and is the source of secondary xylem (wood) inward and secondary phloem outward. It sustains the production of annual growth rings in temperate climates as the cambium activity fluctuates with seasons. The cork cambium, or phellogen, forms a protective outer layer by producing cork cells toward the exterior and phelloderm toward the interior, contributing to the bark.

Cambiais play a central role in the plant’s structural support and water transport, enabling substantial increases in girth and the formation of woody tissues in many dicots and gymnosperms. In monocots, vascular cambium is typically absent, and secondary growth is limited or achieved through alternative meristematic activity, leading to different patterns of plant thickening.

The activity of the cambial tissues is regulated by hormonal signals, notably auxins and cytokinins, and is influenced by environmental conditions such as temperature, water availability, and mechanical stress. Cambial dynamics are a key area of study in plant anatomy, wood science, and paleobotany, helping to explain wood formation, growth rings, and bark development.

See also: cambium, secondary growth, wood anatomy.