. Botany for agricultural students . Botany. SEEDLINGS OF THE GRASS TYPE 103 unfolding its first leaves to the light, a zone, called a node, is formed at its base about 2 inches under the surface of the soil, and from this node and others soon forming above it, there arise roots of a much larger and stronger type than those formed from the radicle and from the stem in the region of the cotyledon. These secondary roots, which are outgrowths of the pliunule since they arise from its nodes, constitute the permanent root system, which as the name suggests remains active as an anchoring and. Fig. 9
. Botany for agricultural students . Botany. SEEDLINGS OF THE GRASS TYPE 103 unfolding its first leaves to the light, a zone, called a node, is formed at its base about 2 inches under the surface of the soil, and from this node and others soon forming above it, there arise roots of a much larger and stronger type than those formed from the radicle and from the stem in the region of the cotyledon. These secondary roots, which are outgrowths of the pliunule since they arise from its nodes, constitute the permanent root system, which as the name suggests remains active as an anchoring and. Fig. 97. — Diagram showing the effect of planting Com at different depths. g, ground hne; p, permanent root system, which always develops at about the same distance under the surface; a, temporary region of the stem, which is much longer in deep planting; fc, kernel; (, temporary root system. Modified from "Elementary Principles of Agriculture" by Ferguson and Lewis. absorptive system as long as the plant lives. After the permanent roots are established (about 10 days after planting) the first roots, which are known as the temporary roots since they serve the plant only till the permanent roots are established, develop no further and remain as vestigial structures until thej' finally disappear. Also included among the temporary structures is the portion of stem between the first node and kernel. {Fig. 96.) During the early stage of germination, this stem portion performs two. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Martin, John N. (John Nathan), b. 1875. New York : John Wiley & Sons, Inc.
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectbotany, bookyear1919
