The Study of Plant Life

by Marie Carmichael Stopes

PART II.
THE PARTS OF A PLANT’S BODY AND THEIR USES

CHAPTER XI.
ROOTS

If you have a garden of your own, or have even watched another person gardening, you must have found out that it is not always an easy thing to get rid of the weeds, and that when one tries to “pull them up by the roots,” they often resist it very strongly indeed. If you have never done this, try to pull up a large grass tuft or a hedge mustard, or any fairly big common plant, and you will find that often when it does not look very strong it may be extremely difficult to get it completely out of the soil, and even when it comes out you may find that you have not got it quite whole, for the finer branches of the root will generally break off. Now this shows us one of the uses of its roots to a plant; they keep it firmly in the soil, and prevent the wind from blowing it away, and people or animals from overturning it too easily.

To see the form of a complete root it is wise to choose a fairly small plant, let us say a daisy, wallflower, candy-tuft, or young holly; then loosen the earth all round it and pull it very gently from the soil. Shake off the mud and then wash it clean and spread it out on a sheet of white paper so that you can examine it properly. Notice that there is a central chief root, with many side branches which have again finer and finer branchlets (see fig. 36). At the tip of the very finest you should see a number of delicate hairs, the root hairs, but it is very possible that you will have torn these off with the soil. To see them best, look at some of your seedlings which have grown in moist air, where they are very well developed (see fig. 8). In any of these plants you will notice that the main root seems to be a downward continuation of the main stem, and that the side roots come off all round it, just as was the case in your bean seedlings (see figs. 36 and 7). Such a root is called a tap root.

Fig. 36. Root of a young Holly: l, level of soil; s, stem; c, chief root with many side branches and finely divided rootlets.

Now dig up a small grass plant and compare its root with these, and you will see that there is no main root, but very many roots coming off in a tuft from the base of the stem, just as was the case in your corn seedlings (see fig. 37). The difference between these roots and tap roots is not of much importance as regards the actual work they do but is one of difference in form; the finer branches in both are very similar and have the same work to do.