Recent research has demonstrated that many plant roots commonly regrow from the same spot on a root, and that they can do this on roots deep below the soil surface. Scientist Richard Zobel from the Agricultural Research Service and Dominick J. Paolillo, Jr., at Cornell University have found evidence of the above in 22 species from 12 families of plants, including: alfalfa, carrots, chicory, Trifolium spp., Coronilla varia, Taraxacum officinale, Aesculus hippocastanum, Pastinaca sativa, Acer spp., and thistles. Adventitious roots were found growing in clusters along older roots. Adventitious roots grow from a different cell layer than the regular, lateral roots, so a plant that has used up the tissue available to grow regular roots can still grow adventitious roots. These roots are called "opportunistic" because they can develop in a matter of hours, to take advantage of sudden environmental changes such as a rare rain in a desert. These roots can sprout on larger roots whose lateral roots have long since died back, enabling the plant to access water and nutrients that have recently become available in those sections of the soil that would otherwise be out of reach. This information could also help scientists introduce adventitious roots to a crop like cotton that apparently is one of the few plants that doesn't have them, as a more efficient way for the crop to grow new roots when rain comes after a dry spell. "FlowerTech" www.HortiWorld.com Further information from Agricultural Research Services, USDA: www.ars.usda.gov