Elements of biology; a practical Elements of biology; a practical text-book correlating botany, zoology, and human physiology elementsofbiolog00hunt Year: [c1907] VIII. BUDS AND STEMS Structural Differences between the Stem and the Root. — Wash carefully the earth from the roots of a pea seedling that you have grown in the laboratory. Try to make out the following points: (1) note the differences in color between the stem and roots; (2) compare the manner in which the root and stem give off lateral branches. Notice that the leaves and lateral branches from a stem are more or less regular in p
Elements of biology; a practical Elements of biology; a practical text-book correlating botany, zoology, and human physiology elementsofbiolog00hunt Year: [c1907] VIII. BUDS AND STEMS Structural Differences between the Stem and the Root. — Wash carefully the earth from the roots of a pea seedling that you have grown in the laboratory. Try to make out the following points: (1) note the differences in color between the stem and roots; (2) compare the manner in which the root and stem give off lateral branches. Notice that the leaves and lateral branches from a stem are more or less regular in position, while the small roots have no regular method of leaving the primary root. The places on the stem where leaves are given off are known as nodes, the part of the stem between being called an internode. In a growing stem of any woody plant, notice the end of the stem; the bud at the termination is a future stem. It is well for us to remember that a stem is a developed bud, as we shall see when we take up the work on the bud more in detail. One difference which is very noticeable between the stem and the root is the color, the young root being whitish or gray, and the young stem being green. The following ex- periment will serv^e to explain this difference: — Effect of Absence of Light on Young Plants. — Plant some peas in sawdust within a box, or wide-mouthed bot- tle which has been previously blackened so that no light is admitted to the interior. Grow some of the same seed in a box alongside the covered material, giving each the same amount of heat and moisture. After the young plants have grown, take one out, compare it with the ones grown in the light, and note the difference in color. Might the absence of light account for the color of the root? The seedlings which have been grown in darkness show some other interesting conditions. The stems are long and more or less reclining on the sawdust. The leaves are hardly worthy of the name, being reduced to little sca
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