A root-hair acts in much the same way as the tube in our experiment

A root-hair acts in much the same way as the tube in our experiment

A root-hair acts in much the same way as the tube in our experiment, with the exception that it is so made as to allow certain substances to pass in only one direction, that is, toward the inside. The outside of the root-hair is bathed in solutions rich in nourishment. The nourishment passes from the outside to the inside through the delicate membrane of the root-hair. Thus does food enter the plant-root. From the root-hairs, foods are carried to the inside of the root.

From this you can see how important it is for a plant to have fine, loose soil for its root-hairs; also how necessary is the water in the soil, since the food can be used only when it is dissolved in water.

This passage of liquids from one side of a membrane to another is called osmosis. It has many uses in the plant kingdom. We say a root takes nourishment by osmosis.

Fonte: Agriculture for Beginners