Kambialvävnaden

Kambialvävnaden, or cambium, is a lateral meristematic tissue found in vascular plants. It is responsible for secondary growth, which increases the diameter of stems and roots. There are two main types of cambium: vascular cambium and cork cambium.

Vascular cambium is typically found between the xylem and phloem in dicotyledonous plants and gymnosperms. It produces new xylem inwards, forming secondary xylem (wood), and new phloem outwards, forming secondary phloem. This process leads to the thickening of the plant body. In woody plants, the accumulation of secondary xylem forms the bulk of the wood.

Cork cambium, also known as phellogen, is another lateral meristem. It arises in the outer tissues of stems and roots, often replacing the epidermis. The cork cambium produces cork cells outwards, which are protective, waterproof, and generally dead at maturity. Inwards, it produces phelloderm, a type of parenchyma. Together, the cork cambium, cork, and phelloderm form the periderm, which is the outer protective layer of woody stems and roots, often referred to as bark.

The activity of the cambial tissues is influenced by environmental factors such as temperature and water availability, leading to the formation of annual growth rings in temperate climates. These rings reflect seasonal variations in cambial activity, with wider, lighter earlywood formed during favorable growing conditions and narrower, darker latewood formed during less favorable conditions.