BOTANY WITH BASICS OF HYDROBOTANY (AQUATIC PLANTS OF UKRAINE) - B.Ye. Yakubenko - 2011

VIII. BASICS OF PLANT MORPHOLOGY AND ANATOMY

Morphology and Anatomy of the Root

Root Growth

The embryonic radicle transforms into the primary ROOT due to an increase in Cell mass. It stands out among the other roots by its vigor and growth rate. Lateral roots branch off from it and, like the primary root, grow from the apex. As a result, the total root length and the absorbing surface of the plant increase. For instance, the roots of wheat and rye reach 600-900 m in length, which increases dramatically thanks to root hairs, bringing the total length to 60 km or even more. Roots expand extensively in space both laterally and longitudinally. In plants of arid habitats, such as The Root System of pine growing on sand dunes, roots penetrate to a depth of 5-20 m, whereas in moderate conditions they reach 4-6 m (apple tree, thistle). However, the bulk of the roots is concentrated in the arable soil layer (0-30 cm). Root growth in the soil is facilitated by both cell proliferation and the presence of a protective root cap.

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Fig. 55. Various root shapes: 1 - napiform, 2 - cylindrical,

3 - conical, 4 - root tubers, 5 - filiform