Question

What is the difference between a meristem culture and a callus culture?

Answer 1

Tissue culture is the process of growing tissues or cells outside of the parent organism in an artificial medium. Micropropagation is another name for this technique. A liquid, semi-solid, or solid growth media, such as broth or agar, is typically used to facilitate this.

Complete answer:
Meristem culture is a tissue culture technique that uses an apical meristem with 1-3 leaf primordia to prepare vegetative propagation clones of a plant. The primary goal of this technique is to isolate the meristem by cutting the stem in a V-shape.
A growing mass of unorganized plant parenchyma cells is known as a plant callus (plural calluses or calli). Callus cells are the cells that cover a plant wound in living plants. Callus formation is induced in vitro from plant tissue samples (explants) after surface sterilization and plating onto tissue culture medium in biological research and biotechnology (in a closed culture vessel such as a Petri dish).
The difference between Meristem culture and a Callus culture is as follows:

Meristem culture	Callus culture
Meristem culture involves the cultivation of differentiated cells.	Callus culture is concerned with the cultivation of undifferentiated cells.
A meristem is made up of cells that are actively dividing. Cell division differentiates the cells into different types of cells, which give rise to different tissues in the mature organ that develops from that meristem.	The proportion of different growth hormones influences callus differentiation.
Meristem culture is the process of growing a bud in a culture medium under aseptic conditions. The meristem already has the cells differentiated to give rise to different shoot tissues, so the bud develops into a shoot in the culture.	If the medium contains auxins only, the callus obtained from tobacco plant pith can differentiate into root cells only, and if the medium contains cytokinins, it can develop into a shoot.
Undifferentiated cells make up the callus. The differentiation of cells and the subsequent formation of calluses are all part of the callus culture process.	If the medium contains a balanced amount of auxins and cytokinins, the callus may develop into a complete plant, as some cells will differentiate into root cells and others into shoot tissue.

Note:
Meristem culture in vitro is the main method used in plant virus elimination programs for the elimination of viruses and related pathogens from a large number of vegetatively propagated plants. The use of callus culture to obtain commercially important secondary metabolites is extremely beneficial. If a small piece of tissue from a medicinally important plant is grown in vitro and turned into a callus culture, secondary metabolites or drugs can be extracted directly from the callus tissue without having to sacrifice the entire plant.