. Botany for agricultural students . Botany. 160 ROOTS creases. They retard absorption and may become so great as to actually prevent it. The wilting of plants when the soil becomes dry is not due to the fact that there is no water in the soil, but to the lact that the roots can not pull the water, known as the un- available water, away from the soil particles. It has been found. Fig. 141. — Lengthwise section through a root, showing the way the water and mineral substances of the soil reach the vascular bundles, e, epidermis with root hairs; c, cortex; a, endodermis; p, pericycle; x, xylem of
. Botany for agricultural students . Botany. 160 ROOTS creases. They retard absorption and may become so great as to actually prevent it. The wilting of plants when the soil becomes dry is not due to the fact that there is no water in the soil, but to the lact that the roots can not pull the water, known as the un- available water, away from the soil particles. It has been found. Fig. 141. — Lengthwise section through a root, showing the way the water and mineral substances of the soil reach the vascular bundles, e, epidermis with root hairs; c, cortex; a, endodermis; p, pericycle; x, xylem of vascular bundle. The arrows indicate the way the water and dissolved substances pass to the vascular bundles. After MacDougal. that most plants wilt when the soil moisture is reduced to per cent in medium fertile garden soil, per cent in sandy loam, and per cent in peaty soil. From these figures it is seen that the amount of unavailable water depends much upon the kind of soil. As shown in the table below, it also depends much upon the kind of plant, for plants differ widely in their ability to pull water away from the soil particles. UNAVAILABLE WATER FOR DIFFERENT PLANTS IN LOAM SOIL Plant. Cabbage Corn Oats Asparagus Lettuce Cucumber Pondweed (a water plant) Unavailable water. Per cent. 24 8. 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.
Size: 1943px × 1286px
Photo credit: © Central Historic Books / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1910, booksubjectbotany, bookyear1919
