Plant tissue culture
Plant tissue culture is a collection of techniques used to maintain or grow plant cells, tissues, or organs under sterile conditions on a nutrient culture medium of known composition. It is widely used to produce clones of a plant in a method known as
- The production of exact copies of plants that produce particularly good flowers, fruits, or other desirable traits.
- To quickly produce mature plants.
- To produce a large number of plants in a reduced space.
- The production of multiples of plants in the absence of seeds or necessary pollinators to produce seeds.
- The regeneration of whole plants from plant cells that have been genetically modified.
- The production of plants in sterile containers allows them to be moved with greatly reduced chances of transmitting diseases, pests, and pathogens.
- The production of plants from seeds that otherwise have very low chances of germinating and growing, i.e. orchids and Nepenthes.
- To clean particular plants of viral and other infections and to quickly multiply these plants as 'cleaned stock' for horticulture and agriculture.
- Reproduce recalcitrant plants required for land restoration
- Storage of genetic plant material to safeguard native plant species.
Plant tissue culture relies on the fact that many plant parts have the ability to regenerate into a whole plant (cells of those regenerative plant parts are called
Techniques used for plant tissue culture in vitro
Preparation of plant tissue for tissue culture is performed under
The composition of the medium, particularly the plant hormones and the nitrogen source (nitrate versus ammonium salts or amino acids) have profound effects on the morphology of the tissues that grow from the initial explant. For example, an excess of auxin will often result in a proliferation of roots, while an excess of cytokinin may yield shoots. A balance of both auxin and cytokinin will often produce an unorganised growth of cells, or callus, but the morphology of the outgrowth will depend on the plant species as well as the medium composition. As cultures grow, pieces are typically sliced off and subcultured onto new media to allow for growth or to alter the morphology of the culture. The skill and experience of the tissue culturist are important in judging which pieces to culture and which to discard.
As shoots emerge from a culture, they may be sliced off and rooted with auxin to produce plantlets which, when mature, can be transferred to potting soil for further growth in the greenhouse as normal plants.[2]
Regeneration pathways
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The specific differences in the regeneration potential of different organs and explants have various explanations. The significant factors include differences in the stage of the cells in the
Shoot regeneration efficiency in
The three common pathways of plant tissue culture regeneration are propagation from preexisting meristems (shoot culture or nodal culture),
The propagation of shoots or nodal segments is usually performed in four stages for mass production of plantlets through in vitro vegetative multiplication but organogenesis is a standard method of micropropagation that involves tissue regeneration of adventitious organs or axillary buds directly or indirectly from the explants. Non-zygotic embryogenesis is a noteworthy developmental pathway that is highly comparable to that of
Choice of explant
The tissue obtained from a plant to be cultured is called an explant.
Explants can be taken from many different parts of a plant, including portions of shoots, leaves, stems, flowers, roots, single
The first method involving the meristems and induction of multiple shoots is the preferred method for the micropropagation industry since the risks of somaclonal variation (genetic variation induced in tissue culture) are minimal when compared to the other two methods. Somatic embryogenesis is a method that has the potential to be several times higher in multiplication rates and is amenable to handling in liquid culture systems like bioreactors.
Some explants, like the
Some cultured tissues are slow in their growth. For them there would be two options: (i) Optimizing the culture medium; (ii) Culturing highly responsive tissues or varieties.[7] Necrosis can spoil cultured tissues. Generally, plant varieties differ in susceptibility to tissue culture necrosis. Thus, by culturing highly responsive varieties (or tissues) it can be managed.[7]
Aerial (above soil) explants are also rich in undesirable microflora. However, they are more easily removed from the explant by gentle rinsing, and the remainder usually can be killed by surface sterilization. Most of the surface microflora do not form tight associations with the
An alternative for obtaining uncontaminated explants is to take explants from seedlings which are aseptically grown from surface-sterilized seeds. The hard surface of the seed is less permeable to the penetration of harsh surface sterilizing agents, such as hypochlorite, so the acceptable conditions of sterilization used for seeds can be much more stringent than for vegetative tissues.
Tissue-cultured plants are
Applications of plant tissue culture
Plant tissue culture is used widely in the plant sciences, forestry, and horticulture. Applications include:
- The commercial production of plants used as potting, landscape, and florist subjects, which uses meristem and shoot culture to produce large numbers of identical individuals.
- To conserve rare or endangered plant species.[8]
- A plant breeder may use tissue culture to screen cells rather than plants for advantageous characters, e.g. herbicideresistance/tolerance.
- Large-scale growth of plant cells in liquid culture in recombinant proteins used as biopharmaceuticals.[9]
- To cross distantly related species by protoplast fusion and regeneration of the novel hybrid.
- To rapidly study the molecular basis for physiological, biochemical, and reproductive mechanisms in plants, for example in vitro selection for stress-tolerant plants.[10]
- To cross-pollinate distantly related species and then tissue culture the resulting embryo which would otherwise normally die (Embryo Rescue).
- For chromosome doubling and induction of antimitotic agents such as colchicine or oryzalin.
- As a tissue for transformation, followed by either short-term testing of genetic constructs or regeneration of transgenicplants.
- Certain techniques such as meristem tip culture can be used to produce clean plant material from virused stock, such as sugarcane,[12] potatoes and many species of soft fruit.
- Production of identical sterile hybrid species can be obtained.
- Large scale production of artificial seeds through somatic embryogenesis[13]
Examples
Developing Somaclonal variation
| Plant | Somaclonal variant | Traits |
| Sugarcane | 'Ono' | resistance to Fiji disease. |
| Citronella java | 'Bio-13' (by CIMAP , Lucknow) | 37% more oil |
Climate resilience
- As in Kaveri Vaman (by NRCB , Tamil Nadu) , a Tissue Culture Banana Mutant to withstand heavy rains.[14]
Secondary metabolites production
- Such as Caffeine from coffea arabica, Nicotine from Nicotiana rustica.
Induction of flowering
- In trees with delay in flowering or Bamboo - where some species flower once in their life but may live longer than 50 years.[15]
See also
- Hairy root culture
- Gottlieb Haberlandt, pioneer of plant tissue culture
- Frederick Campion Steward, pioneer and 'champion' of plant tissue culture.
- Murashige and Skoog medium and Hoagland solution, important plant growth media
- Plant physiology
References
Notes
- ISBN 978-81-89866-11-2.
- ISBN 978-0-444-81623-8.
- ISSN 1573-5044.
- S2CID 20181898.
- ^ Brian James Atwell; Colin G. N. Turnbull; Paul E. Kriedemann (1999). Plants in Action: Adaptation in Nature, Performance in Cultivation (1st ed.). Archived from the original on March 27, 2018. Retrieved May 7, 2020.
- ISBN 978-0-7923-2493-5.
- ^ .
- .
- S2CID 30677496.
- .
- S2CID 9211804.
- ^ Pawar, K. R., Waghmare, S. G., Tabe, R., Patil, A. and Ambavane, A. R. 2017. In vitro regeneration of Saccharum officinarum var. Co 92005 using shoot tip explant. International Journal of Science and Nature 8(1): 154-157.
- ^ Waghmare, S. G., Pawar, K. R., and Tabe, R. 2017. Somatic embryogenesis in Strawberry (Fragaria ananassa) var. Camarosa. Global Journal of Bioscience and Biotechnology 6(2): 309 - 313.
- ISSN 0971-751X. Retrieved 2023-08-31.
- ISBN 978-1-4020-3213-4.
Sources
- George, Edwin F.; Hall, Michael A.; De Klerk, Geert-Jan, eds. (2008). Plant propagation by tissue culture. Vol. 1. The background (3rd ed.). Springer. ISBN 978-1-4020-5004-6.
- Yadav, R.; Arora, P.; Kumar, D.; Katyal, D.; Dilbaghi, N.; Chaudhury, A. (2009). "High frequency direct plant regeneration from leaf, internode, and root segments of Eastern Cottonwood (Populus deltoides)". Plant Biotechnology Reports. 3 (3): 175–182. S2CID 42796629.
- Singh, S.K.; Srivastava, S. (2006). Plant Tissue Culture. Campus Book International. ISBN 978-81-8030-123-0.
