Asexual Propagation: Tissue Culture

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Also called micropropagation, tissue culture is the production of plants under sterile laboratory conditions. A variety of tissue culture techniques are used to propagate plants. In one method, growers remove a tiny piece of leaf or stem from a plant and place it in a sterile test tube on a gel-like medium enriched with hormones and nutrients. A yellow-brown mass of cells called callus develops from the piece of plant. Small chunks of the callus are separated, and each piece is placed in a petri dish with a hormone and nutrient mix that stimulates the development of the callus pieces into plants. The young plants are removed from the petri dish and placed in pots with soil, or into the ground, where they grow to maturity.

Tissue culture enables researchers and growers to rapidly generate numerous clones year-round in greenhouses. In nature, strawberry plants typically produce their fruits in summer. Commercially grown strawberries, however, are propagated throughout the year by tissue culture, providing consumers with a steady supply of strawberries for every season. Tissue culture is also used to produce plants free of viruses, fungi, and bacteria, and to propagate species such as Douglas fir and rhododendron, which are difficult to grow commercially from cuttings, layering, or grafting.


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