The roots of most terrestrial plants are deeply and widely distributed underground, forming a huge root system, which is more developed than the above-ground branch system. It can be described as "deep roots" and "deep roots of trees", which shows the important role of roots in plant growth. The main functions of roots are as follows:

Absorption: The main function of roots is to absorb water and inorganic salts from soil.

Fixation and support: the root system is deeply rooted in the soil, and the huge root system in the form of repeated branches is isomorphic with the mechanical tissue in the root to form the fixing and support part of the plant, so that the plant can be fixed in the soil and made upright.

Storage and propagation: Roots often have storage function because of their well-developed parenchyma. Storage materials include sugar (beet), starch (sweet potato), vitamins and carotene (carrot). Of course, water is the most abundant in roots.

In addition, the roots of some plants also have reproductive function, and their roots are easy to germinate to form adventitious buds, and then form new branches (such as poplar and Robinia pseudoacacia). This characteristic of roots can be used for cutting propagation of plants.

So the answer is: