Museum case showing models of roots and tubers and illustrations of roots and soil.

Section of root with root hair

Sandy soil does not hold water. Clay soil excludes air. Since the presence of both is necessary, here are percentages of water and air, together with rock particles and humus, for an ideal loam soil.

(Disk shows proportions of water, air, humus, and rock particles in the soil.)

Root Tip

Enlarged 44 times showing root hairs and protective cap at the lower end.

All absorption of water takes place through tiny root hairs which are found only near the ends of the smallest rootlets. These root hairs are outgrowths of the epidermal cells.

Roots in the soil. Roots, tubers and bulbs.

Roots, tubers, and bulbs

Some roots are storage roots holding starches, sugars, or proteins for the next year's growth. Some vegetables that look like roots are really not roots but bulbs, such as the onion, or tubers, such as the white potato. Bulbs store food in fleshy underground leaves, and tubers are thickened underground stems.




White potatoes




Roots serve as anchorage for plants and help to reduce soil erosion. But their chief function is to absorb water from the soil, thereby obtaining nutrients in solution for nourishment.