Plant culture. Test tubes containing plant seedlings with a pipette being inserted into one of them. The gel in the test tube is a soil- substitute containing the nutrients needed by the growing plant. Plants can be grown in this way from a tiny fragment or single cell of a parent" plant in a process called micropropagation. Carefully controlled conditions cause the fragment to develop into an embryo which then produces roots and shoots like a normal seedling. The technique allows mass agricultural production of genetically identical plants and is an effective way of propagating any genes introduced into the parent plant."