Root-tubercles

Tubercle is a big word, but you ought to know how to pronounce it and what is meant by root-tubercles. We are going to tell you what a root-tubercle is and something about its importance to agriculture. When you have learned this, we are sure you will want to examine some plants for yourself in order that you may see just what tubercles look like on a real root.

Root-tubercles do not form on all kinds of plants that farmers grow. They are formed only on those kinds that botanists call legumes. The clovers, cowpeas, vetches, soy beans, and alfalfa are all legumes. The tubercles are little knotty, wart-like growths on the roots of the plants just named. These tubercles are caused by tiny forms of life called, as you perhaps already know, bacteria, or germs.

Fig. 23. Tubercles on Clover Roots

Fonte: Agriculture for Beginners