Cambium

Cork cambium 1

Cambium is a type of meristematic tissue in plants that is involved in the secondary growth, producing wood and phloem. It is a layer of undifferentiated cells that divide to produce new cells, which then differentiate into various cell types. Cambium plays a crucial role in increasing the diameter of stems and roots in woody plants. There are two main types of cambium found in higher plants: the vascular cambium and the cork cambium.

Vascular Cambium

The vascular cambium is located between the wood (xylem) and the bark (phloem) in the stems and roots of dicotyledonous and gymnosperm plants. It is responsible for producing secondary xylem (wood) towards the inside and secondary phloem towards the outside. This process results in the thickening of the stem or root, contributing to the overall growth of the plant. The vascular cambium is a continuous layer of cells that forms a cylinder along the length of the stem and root.

Cork Cambium

The cork cambium, also known as phellogen, is found in the outer cortex region of stems and roots. It produces cork (phellem) cells towards the outside, which replace the epidermis in mature stems and roots, and phelloderm cells towards the inside. The cork cambium contributes to the formation of the periderm, a protective layer that helps in reducing water loss and protecting the plant against pathogens and physical damage.

Function and Significance

The cambium is significant for several reasons:

• It contributes to the increase in girth of the plant, supporting larger plant structures.
• The secondary xylem produced by the cambium is an essential component of wood, which has significant economic value for construction, paper production, and other uses.
• The secondary phloem helps in the transport of nutrients and sugars produced by photosynthesis to different parts of the plant.
• The cork cambium's production of a protective layer helps the plant to survive in various environmental conditions.

Regulation

The activity of the cambium is regulated by various internal and external factors, including plant hormones like auxin, cytokinin, and gibberellin, as well as environmental conditions such as light, temperature, and availability of nutrients. The balance between these factors determines the rate of cell division in the cambium and, consequently, the rate of growth of the plant.

Research and Applications

Research on cambium and its regulation can lead to advances in forestry and agriculture, such as improving wood production, developing resistance to pests and diseases, and enhancing plant growth under various environmental conditions.

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