Roots: Approximately 1/3 of a plants biomass is invested in roots... this proportion may vary widely however, approaching close to 2/3 of the mass in grasses of the plains, and down to negligible amounts in epiphytes which reside on tree. Primary functions of roots include:

1. Anchorage; critical role especially where climate may be severe-- windy, frost-heaving areas, where soils are difficult to hold onto ( i.e. sandy or aquatic areas)

2. water and mineral Absorption:

• partially but not totally a passive process- in some cases plants will invest energy into excluding toxic substances ( salts,toxins)
• absorption may be aided through mycorrhizal associations, which we investigate later

3. Storage- critical reserves of food especially for perennials ( trees [ 2-3 years worth]; grasses, biennials which overwinter)

4.Production of various chemicals involved in growth ( hormones) and defense ( competition, antimicrobial). Root competition may be quite intense when nutrients are low and density of life is high. Species can produce toxic or inhibitory chemicals which will retard or kill tissue of competing roots.

5. Transport of materials up, down, and laterally.. Conduction-Roots transport water and dissolved nutrients to and from the shoot. The roots of plants can even transport carbon dioxide for photosynthesis. The leaves of these specialized plants usually have thick cuticles and lack stomata.

Natural grafting: Some question the individuality of root systems: recent studies indicate that tree roots fuse between individuals of the same and other species, with storage products as well as microbes transmitted from one to another. This process may be regulated via the mycorrhizal associations rather than by the plants themselves, putting into question, 'who controls the forest'?.