Tissue culture is a technique used to grow cells, tissues, or organs in a nutrient medium under sterile conditions. There are several types of tissue cultures, each suitable for different purposes and plant or animal tissues. Here’s an overview of the main types along with their maintenance:


Types of Tissue Cultures

  1. Callus Culture

    • Description: A callus is an unorganized mass of cells that is produced when tissues are grown in an appropriate medium. It is often used for studying cellular differentiation and regeneration.
    • Maintenance: Requires regular subculturing to maintain active growth, generally every 3-4 weeks. The callus should be kept in a sterile environment with optimal temperature and photoperiod conditions.

  2. Organ Culture

    • Description: In this type, whole organs or parts of an organ are cultured in vitro to maintain its structure and function. It is often used for developmental studies.
    • Maintenance: Careful attention is required to maintain the integrity of the organ. Fresh nutrient medium needs to be provided at regular intervals, and conditions such as humidity, temperature, and sterility must be maintained.

  3. Cell Suspension Culture

    • Description: This involves single cells or small clusters suspended in a liquid medium, often agitated to keep the cells uniformly distributed. This culture type is useful for mass production of plant cells or secondary metabolites.
    • Maintenance: Requires constant agitation using shakers to ensure oxygen and nutrient availability. The culture needs frequent subculturing to maintain cell viability and prevent overgrowth.

  4. Protoplast Culture

    • Description: Protoplasts are plant cells with their cell walls removed, used to study cell wall regeneration, fusion, and genetic transformation.
    • Maintenance: Protoplasts are delicate and need an osmotic stabilizer in the culture medium. They require a controlled osmotic environment and careful monitoring to prevent bursting or lysis.

  5. Embryo Culture

    • Description: Used for embryos that may not develop fully in vivo, such as in cases of interspecific hybridization where seed formation may be unsuccessful.
    • Maintenance: Requires a nutrient-rich medium, free from inhibitors that might impair development. Optimal temperature and growth hormones must be controlled to facilitate embryo development.

  6. Anther and Pollen Culture

    • Description: This technique involves culturing anthers or isolated pollen to produce haploid plants, useful in breeding programs.
    • Maintenance: Culture conditions must be sterile, and a medium supplemented with appropriate plant growth regulators is needed. The temperature is generally altered to induce stress, which can promote haploid formation.

  7. Shoot Tip and Meristem Culture

    • Description: Involves the culture of shoot tips or meristems, primarily used for virus elimination and clonal propagation.
    • Maintenance: Requires a nutrient medium enriched with cytokinins to promote shoot proliferation. Regular transfer to fresh media is essential to avoid nutrient depletion and growth inhibitors.

Maintenance of Tissue Cultures

  1. Sterility

    • The most crucial aspect of maintaining tissue culture is avoiding contamination. This is done by using autoclaved equipment, sterile laminar airflow hoods, and frequent disinfection procedures.

  2. Subculturing

    • Cultures need to be regularly subcultured to fresh media to ensure continued growth. This also helps prevent the buildup of toxic metabolites.

  3. Nutrient Medium

    • The composition of the nutrient medium varies depending on the tissue type, including macro- and micronutrients, vitamins, amino acids, and plant growth regulators like auxins and cytokinins.

  4. Environmental Conditions

    • Most tissue cultures are grown at temperatures between 20-27°C, with specific light cycles (usually 16 hours of light and 8 hours of darkness) and appropriate humidity levels. The pH of the culture medium also needs to be monitored and adjusted, typically kept between 5.6 and 6.0 for plant tissue cultures.

  5. Monitoring Growth

    • Regular monitoring for changes in color, morphology, or signs of contamination helps in maintaining healthy cultures. Adjusting hormone levels or other nutrients is often necessary to promote desired growth responses.

Maintaining tissue culture requires careful control of environmental and nutritional conditions to support cell growth and differentiation. Ensuring a sterile environment and using appropriate growth regulators are key to achieving successful outcomes in tissue culture experiments.