. A practical course in botany, with especial reference to its bearings on agriculture, economics, and sanitation. Botany. minating grains of barley, wheat, corn, rice, etc. By the presence of diastase starch is converted into grape sugar, a substance which is readily soluble in water, and which can be diffused easily through the tissues of the plant to any part where it is needed. In this way food travels from the leaf, where it is made, to the seed, where the sugar is generally reconverted into starch and stored up for future use, though some- times, as in the sugar corn and sugar pea, it re
. A practical course in botany, with especial reference to its bearings on agriculture, economics, and sanitation. Botany. minating grains of barley, wheat, corn, rice, etc. By the presence of diastase starch is converted into grape sugar, a substance which is readily soluble in water, and which can be diffused easily through the tissues of the plant to any part where it is needed. In this way food travels from the leaf, where it is made, to the seed, where the sugar is generally reconverted into starch and stored up for future use, though some- times, as in the sugar corn and sugar pea, it remains in part unchanged. The kernels of this kind of corn can be distinguished readily from those of the ordinary starch corn, after maturity, by their wrinkled appear- ance', owing to their greater loss of water in drying. 10. Food tests. — In or- der to tell whether any of the food substances named occur in the seeds that we are going to examine, it will be necessary to understand a few simple tests by which their presence may be recognized. The chemicals required can be ordered ready for use from a druggist or may be prepared in the laboratory as needed, according to the directions given. Write in your notebook a brief account of each ex- periment made, with the conclusions drawn from it. Experiment 1. To detect the presence of fats. — Rub a small lump of butter or a drop of oil on a piece of thin white paper. What is the effect ? Experiment 2. Another test for fats. — Place some macerated alcanna root in a vessel with alcohol enough to cover it, and leave for an hour. Add an equal bulk of water and filter. The solution will stain fats, oils, and resins deep red. Fig. 12.— Starch grains of wheat in different stages of disintegration under the action of a ferment (diastase), accompany- ing germination : u, slightly corroded ; b, c, and d, more advanced stages of decomposi- Please note that these images are extracted from scanned page images that may have been d
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