Callus (cell biology)

In botany, the term callus (also callus, calli and calli majority ) are used for different situations:

As callus wound tissue

As the undifferentiated callus, parenchymal cell complexes are identified by non-directional growth, which may occur after an injury. Callus tissue closes the wound and therefore contributes significantly to wound healing. In woody plants, the callus is formed from the cambium, in herbaceous plants from the parenchyma by hypertrophic growth of the uninjured border cells and subsequent intensive cell division.

Callus as tissue culture

As callus in botany, a complex of undifferentiated, totipotent cells designated which is composed of a piece of tissue or a cell which has been previously taken from a living plant, develops. This piece of tissue is placed in an artificial soil, the mineral salts and organic compounds such as sugars and plant hormones contain that allow callus growth only. These hormones occur naturally in coconut water, are in the natural form, however not as efficient as with synthesized hormones. Since the cells of a callus produced by mitosis, they should not differ genetically. However, it often results in the formation of polyploid cells in calli. Even aneuploidy and ring chromosome formation has been reported. Herbs seem to have a higher susceptibility than tree species va For a change in chromosome number have conifers by Kalluszüchtung.

The callus encountered mainly in plant research with great interest, because with its help plant tissue without a living host may be grown. After a few weeks, it is possible to replace parts of the callus tissue and this weiterzukultivieren separately to obtain more tissue cultures.

By adding phytohormones differentiation of cells and thus, for example, a living plant shoot can occur.

Prior to regeneration to a fertile plant calli can be used as a transformation target. These are primarily the biolistic transformation or transformation with Agrobacterium used. It is also a transformation with silicon carbide crystalline needles.

Callus as a thickening of plant organs

In addition to calluses or thickened areas on leaves, flowers or other plant organs, for example, on the lip of orchids, also called callus.