Root plant to fuel the process. In return, the plant takes nitrogen compounds produced from ammonia by the bacteria. The term root crops refers to any edible underground plant structure, but many root crops are actually stems, such as potato tubers. Edible roots include cassava, sweet potato, beet, carrot, rutabaga, turnip, parsnip, radish, yam and horseradish. Spices obtained from roots include sassafras, angelica, sarsaparilla and licorice. Sugar beet is an important source of sugar. Yam roots are a source of estrogen compounds used in birth control pills. The fish poison and insecticide rotenone is obtained from roots of "Lonchocarpus" spp. Important
Cutting (plant) of a plant that is not a root; these roots can form as part of normal development or due to a stress response. Adventitious root formation from the excised stem cutting is a wound response. At a molecular level when a cutting is first excised at the stem there is an immediate increase in jasmonic acid, known to be necessary for adventitious root formation. When the cutting is excised from the original root system the root inhibiting hormones, cytokinin and strigolactone, which are made in the root and transported to the stem, decrease in concentration. Polyphenol degradation decreases, increasing auxin