2. Explant
• The tissue obtained from a plant to be cultured is called an explant.
• Explants are small pieces of plant parts or tissues.
• Are aseptically cut and used to initiate a culture in a nutrient
medium.
• Explants can be taken from different parts of a plant such as:
• shoots, leaves, stems, flowers, roots, and from many types of mature
cells provided they are able to de-differentiate into totipotent cells.
3. Selection of Explants:
• The correct choice of explant material can have an important effect
on the success of tissue culture. The choice of explants depends on:
1) the kind of culture to be initiated
2) the purpose of the proposed culture
3) the plant species to be used
4.
5. Conti..
• For successful culture initiation, there is a minimum size for explant
per unit culture volume.
• In practice, minimum inoculation size of explant varies according to
the genotype of the plant being cultured and the cultural conditions.
• For commencing suspension cultures it is commonly about 1-1.5 x
104 cells/ml.
6.
7. Contamination Free
• Plants growing in the external environment are invariably
contaminated with micro-organisms and pests.
• These contaminants are mainly confined to the outer surfaces
of the plant, although, some microbes and viruses can even
grow within the root.
8. Conti….
• Most of the surface microbes do not form tight associations with the
plant tissue.
• They are easily removed from the explant by gently rinsing, and the
remaining are killed by surface sterilization.
• Placing the explant in a 70% ethyl alcohol solution prior to treatment
with another disinfectant solution.
• Conducting the sterilization process under vacuum.
• This results in the removal of air bubbles and provides a more efficient
sterilization process.
