what is callus in plants

A plant callus is a mass of unorganized plant parenchyma cells that forms in response to a wound or cut on a plant surface. It is a result of cellular/tissue reprogramming due to conditions overriding cell/tissue differentiation constraints, such as hormone gradients and chromatin). Callus cells are those that cover a plant wound and can be induced from plant tissue samples after surface sterilization and plating onto tissue culture medium in vitro). The culture medium is supplemented with plant growth regulators, such as auxin, cytokinin, and gibberellin, to initiate callus formation or somatic embryogenesis). Callus is of particular use in micropropagation, where it can be used to grow genetically identical copies of plants with desirable characteristics). When a callus forms, some of its cells may organize into growing points, some of which in turn give rise to roots while others produce stems and leaves, making callus capable of regenerating an entire plant. Callus is a valuable tool in plant biotechnology and research, providing a means to study cellular/tissue reprogramming and regeneration processes in plants.