Democratic Sentinel, Volume 14, Number 51, Rensselaer, Jasper County, 9 January 1891 — The Direction of Growth in Roots. [ARTICLE]

The Direction of Growth in Roots.

While it is the rule for primary roots, or those, fi)cst developed, to grow downward, the secondary branches usually tend to assume a direction almost at right angles to the vertical, and so grow outw'ard and a little downward, as if they were but slightly susceptible to the action of gravity, while tertiary branches, and the farther branches to which these give rise, grow in all directions quite independent of grayity. It is plain that as a result of these peculiarities the active parts of the roots are distributed in such a manner as to searph the surrounding earth more thoroughly than otherwise would be possible. In case a stone or other obstruction is encountered by any of the branches, the tip is turned aside and follows the contour closely until the edge is reached, when it soon assumes its proper direction. Not infrequently it must happen that some root - eating animal will destroy the end of a young primary root, and so endanger the proper development of the whole system, but experiment has shown that, in the event of such injury, one of the younger secondary branches changes its direction of growth, so as to point directly downward, and thus assume the function of the primary root to promote the search for food in the deeper regions. - Popular Science Monthly