Chapter 20

Vegetative Plant Propagation

Plant Propagation by Tissue Culture

Tissue culture, or micro-propagation, is the art and science of propagating plants in vitro, which means “within the glass,” in this case, a propagation tube (See Figure 20.16). Tissue culture techniques allow thousands of new plants to be obtained from a single plant, making the technology attractive to rapidly multiply new cultivars. Its limitations include the need for specialized equipment and facilities along with a great deal of highly skilled labor. The tissue culture process can be divided into four steps or stages: 1) explanting, 2) multiplication, 3) organogenesis, and 4) acclimatization.

Explanting and Culturing

The piece of tissue (cell or cells) taken from a plant to be used in tissue culture propagation is known as the explant. This often is the apical meristem, but it can be other plant tissue. Explants should only be taken from healthy plants and need to be surface sterilized before use. After sterilization, the explant is placed on the surface of the sterilized medium in the culture tube. Multiplication involves wounding plant tissue to induce cellular division forming an undifferentiated mass of cells known as a callus. This callus continues to grow in size during the multiplication stage.

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