Plant Tissue Culture Types

Callus Culture 

A callus is an unorganized mass of cells that develops when cells are wounded. When the explant is cultivated on media that promote the development of undifferentiated cells, a callus is formed. The majority of callus cells are formed with the aid of auxins and cytokinins. Using plant growth hormones, callus can multiply continuously or be directed to develop organs or somatic embryos. 

Cell Suspension Culture

Small fragments of loose friable callus can be cultured as cell suspension cultures in a liquid medium. Cell suspensions can be maintained as batch cultures grown in flasks for long periods. A portion of callus tissue can be transferred into a liquid medium, and when subjected to continuous shaking, single-cell cultures and suspension cultures can be cultivated from callus cultures. The growth rate of the suspension-cultured cells is generally higher than that of the solid culture. 

Anther/Microspore Culture

The culture of anthers or isolated microspores to produce haploid plants is known as anther or microspore culture. Embryos can be produced via a callus phase or be a direct recapitulation of the developmental stages characteristic of zygotic embryos. Compared to traditional breeding methods, microspore culture enables the creation of homozygous plants in a very short time. These homozygous plants are useful tools in plant breeding and genetic studies. 

Protoplast Culture

Protoplasts contain all the components of a plant cell except for the cell wall. Protoplasts can be used to create somatic hybrids and regenerate whole plants from a single cell. Cell walls of explant can be removed either mechanically or enzymatically. Protoplasts can be cultured either in liquid or solid medium. Protoplasts embedded in an alginate matrix and then cultured on a solid medium have better success rates of regeneration. Although protoplasts appear to be a very appealing method for regenerating plants and transferring genes, they are extremely delicate.

Embryo Culture

It is a technique in which isolated embryos from immature ovules or seeds are cultured in vitro. For species whose seeds are dormant, resistant, or prematurely sterile, embryo culture has been used as a helpful tool for direct regeneration. In plant breeding programs, embryo culture goes hand in hand with in vitro control of pollination and fertilization to ensure hybrid production. In addition, direct somatic embryos and embryogenic calluses can be produced from immature embryos.

Meristem Culture

Using apical meristem tips, it is possible to produce disease-free plants. This technique can be referred to as meristem culture, meristem tip culture, or shoot tip culture, depending on the actual explant used. Plant apical meristems make good explants for the cultivation of virus-free plants. Hence, this method is usually used to eliminate viruses in many species.