Rhizoids also absorb water but totally lack vascular tissues.
In addition, parasitic plants may form specialized haustorial roots that form an attachment disc to the host during the first stage of colonization. To absorb water and dissolved minerals, a young sector of a root commonly possesses numerous single-celled projections called root hairs , which greatly increase the absorbing surface of the root and achieve much greater contact with soil particles. Both young and old roots can be important repositories for carbohydrates, usually in the form of starch grains located in root cortex, but in addition older roots may store massive quantities of starch and even become specialized below-ground storage organs. Storage of carbohydrates in roots and other below-ground plant organs is an important plant strategy for surviving stress and dormancy, just as certain mammals store extra fuel as fat for winter. Roots may be assisted in their function by other organisms living in the substrate.