Even if the cell walls of the mesophyll that border on the intercellular space are taken into account, is the absorbing surface of the root still 22 times as big as the transpiring surfaces of the shoot. This may look uneven, since it enables the plant to a water uptake much larger than its water transpiration. But the calculation includes many elements of uncertainty. It assumes, for example, that all root hairs are equally active. It would therefore certainly be desirable to redo such a calculation with data from another plant of the same or another species to be able to estimate the error rate and to find out whether the calculation can be generalized.
Root hairs are always in close contact with soil particles.
They are often grown in together and it is thus impossible to isolate a root that has been grown in the soil without impairing it. Root hairs produce as a rule carbohydrate-containing mucigel . It generates a rhizosphere , where nutriments can be processed before uptake by the plant. Another specialized cell in the root is the endodermal cell. The endodermis forms a cylinder around the vascular cylinder in the roots.