Vascular cambium

Cambium (Latin cambium = change), or Kambiumring, called especially in trees - the hollow cylindrical growth layer between the bark and the Splintholzzone ( Bastzone and bark ).

This layer is responsible for the secondary shoot growth ( lateral growth ). It can be called secondary or Lateralmeristem in contrast to the primary apical meristem. It lies between the xylem (inside) and phloem ( outwards). In most of the monocotyledonous plants there are no cambium in vascular bundles ( xylem / phloem ), and therefore they are not capable of growth in thickness to a secondary shape of dicotyledonous plants.

The cambium is in an early development stage of a dicotyledonous plant only available as so-called fascicular cambium and is located within the vascular bundles (Latin fasces ). In the course of further development occurs - about hormonal influences and a Remeristematisierung - from already differentiated cells of the parenchymatous medullary ray tissue in the amount of fascicular cambium another meristematic tissue. This is called Interfascicular cambium. Fascicular cambium and Interfascicular together form the closed Kambiumring a dicotyledonous plant.

There are monocotyledonous plants such as palm trees, which have a massive primary growth in thickness. However, this is done by the apical meristem. As a result, the scion from the beginning to the almost maximum diameter. Some monocots have by vegetative growth and accumulation of dead leaf sheaths on an apparent secondary growth. This occurs, for example in Palm lilies, dragon trees or Elephantenfuß. For a secondary growth, a closed Kambiumring is required, which forms uniformly along the entire circumference of new cells inside and outside and releases. The existing part of the Kambiumsrings, which lies between the xylem and phloem within the vascular bundle is called a fascicular cambium. Thus, a closed Kambiumring arises the parenchymal cells of the medullary rays are remeristematisiert by hormonal stimuli and form a so-called consecutive Interfascicular cambium.

According to the definition is all the tissue that is deposited from the cambium to the inside, called wood ( secondary xylem = ) (regardless of the lignification ) and all tissue, which is deposited outward Bast ( = secondary phloem ). In Bast may develop an additional cambium, cork cambium are secondary ( cork cambium ).