Meristem culture particularly involves the cultivation of the shoot apical meristem. This technique also refers to Shoot tip or Apical meristem culture. In 1952 Morel and Martin were the first scientists who developed the technique of meristem culture for in-vivo virus eradication of Dahlia. Orchid cymbidium was micropropagated using this culture by Morel in 1965.
The meristem can culture by isolating from the stem by applying a V-Shape cut. In this technique, by the culturing of shoot meristem, adventitious roots can regenerate. The size of shoot tip is 10mm for the generation of the virus-free plant, and for vegetative propagation, the size of the shoot tip does not matter.
The technique of meristem culture is very much similar to the technique of micropropagation which also involves:
- Initiation of culture
- Multiplication of culture
- Rooting of a developed shoot
- Transfer of plantlets to the pots
For the regeneration of plant by the meristem culture, the most widely used medium is Murashige and Skoog’s (MS) medium with low salt concentration for the majority of the species. Fungicides (Bavistin) or antibiotics (chloramphenicol or streptomycin) uses to remove the endophytic contamination.
Content: Meristem culture
- Definition of Meristem culture
- What is Meristem?
- Process of Meristem culture
Definition of Meristem culture
Meristem culture can define as the tissue culture technique which makes the use of apical meristem with 1-3 leaf primordia by which clones of a plant can develop by the vegetative propagation.
What is Meristem?
Meristem is the part of a plant which plays a key function to increase the plant length. It composes of cells refers to a meristematic cell which are the continuous cells that are oval, polygonal, rectangle in shape. There is no intercellular space between the meristematic cells.
Meristem is the shoot tip or the apical region which is found at the shoot apical and root apical region. It is “Dome-shaped” whose thickness is about 0.1 mm in diameter and 0.25-0.3 mm in length.
The apical shoot meristem is the portion where a stem elongates and is free of pathogens which were proved in 1949, before the introduction of meristem culture. Limmaset and Cornuet were the two scientists who observed the declined growth of virus towards the apical meristem. For this reason, meristem culture is very popular among other techniques in the production of virus and other related organisms free plants.
Process of Meristem culture
The process of meristem culture technique involves the following steps:
- Remove the young twigs from the healthy plant.
- Cut the tip portion of the twig that should be of 1cm.
- Subject the shoot tip to the surface sterilization in the sodium hypochlorite solution for 10 minutes.
- Rinse the explants thoroughly with the distilled water for about 4 times.
- Then, transfer each explant to a sterilized Petri plate.
- Dissect the outer leaves of the shoot tip.
- After the dissection of outer leaves, the apex region will get exposed which is separated by the help of a scalpel.
- Transfer the apex or apical meristem to the MS (Murashige and Skoog’s) nutrient medium.
- Incubate the culture under 16 hours light at 25֯ C.
- After the development of single or multiple shoots, transfer it to the hormone-free medium for the root development.
- Then, transfer the plants to the pots containing compost and kept under greenhouse condition for hardening.
By the Meristem culture, virus-free plants can grow. The meristem from a plant which produces heterozygous seeds can store in the in-vitro conditions.
Meristem culture also helps in the plant breeding technique where hybrid breeds of the plants can grow. The quarantine authority for the international exchange easily accepts the plants obtained by the meristem culture.
- Apical shoot culture also helps in the production of virus-free plants.
- The germplasm or the seeds can conserve in-vitro or by cryopreservation method.
- Meristem contains high auxin concentration which promotes plant growth.
- Isolation of meristem is quite difficult.
- Explants take more regeneration time to grow.
It is a very effective method in the field of agricultural and industrial science, by which clones of a plant can prepare and disease resistant plants can also develop.
For example, Tobacco Mosaic Virus has been eliminated from the petunia species of the plant, Cauliflower Mosaic Virus has been eliminated from the Brassica oleracea plants etc.