How is Tissue Culture Done?
Tissue culture is an important component of transforming plants with new genes.
During this procedure, plant cells can be removed from various parts of a plant and placed on media in petri plates. The media does not contain the growth hormones normally present in a plant that tell the cells which tissue to develop into. As a result, the cells do not differentiate and instead form a mass of cells called a callus that are not differentiated into at the tissue level.
Cells are taken from plants and grown into undifferentiated masses called callus. (Image by P. Hain)
Immature embryos are removed from seeds and placed on media. Callus cells will then begin to grow from them. (Photo by T. Weeks)
Callus are masses of undifferentiated cells. (Photo by T. Weeks)
Since plant cells are totipotent, growth hormones can be added to the media triggering the callus cells to develop roots, shoots and eventually entire plants. Plants regenerated from tissue culture will be clones genetically identical to the cell they originated from. The only animal cells that have this totipotent characteristic are fertilized eggs.
Single cells can be regenerated into entire plants. (Image by P. Hain)
Growth hormones can be added to the media and the cells will begin to divide and differentiate into plants. (Photo by T. Weeks)
Regenerated plants are then transferred into test tubes. Once they have reached a certain size, they will be transplanted into soil. (Photo by T. Weeks)