Plants tissue culture..........

Plant tissue culture is the technique to grow plant cells, tissues or organs under sterile conditions on a nutrient culture medium of known composition.

Plant tissue culture is widely used to produce clones of a plant in a method known as micropropagation. These new plantlets are grown in a short period of time, and they are free of soil-borne pathogens.
Sterile agar gel, plant hormones, and nutrients is needed for this objective. So. it makes tissue culture expensive and difficult than taking plant cuttings. However, its used widely, for different goals, including clonal propagation and genetic alteration for better vigor against pathogens/pests.
Four steps of tissue culture techniques:
1. Inoculation of explant 2. Incubation of culture 3. Sub-culturing 4. Transplantation of the regenerated plant.

(http://askmissteong.blogspot.com/2013/01/plant-tissue-culture-recommended-videos.html)

Step 1. Inoculation of explant:

The sterilized explants are transferred to the nutrient medium.

Step  2. Incubation of culture: 

After inoculation, the cultures are incubated in culture room or in incubator. Low humidity can cause desiccation, while high humidity can lead to microbial contamination.

Step 3. Sub-culturing:

The progress of the in vitro-grown tissues are monitored periodically.

For suspension culture, media is changed.

For callus culture, the sub-culturing of the callus tissue is performed.

Step 4. Transplantation of the regenerated plant:

Plants regenerated from in vitro tissue culture are transplanted to soil.  Acclimatization of these regenerated plants are conducted to get it prepared for survival in the field conditions.