. Botany for agricultural students . Botany. SECRETIONS 285 A number of enzymes, such as diastase, invertase, maltase, zymase, and cytase, are involved in the digestion of the carbo- hydrates. Diastase, which is especially abundant in germinating seeds, changes starch into sugar. Invertase converts cane sugar into glucose and fructose, and maltase converts maltose into glucose. Zymase, well known as a secretion of the Yeast plant, converts sugar into alcohol and carbon dioxide. Cytase breaks cellulose into simpler compounds. The lipases digest the fats by changing them into fatty acids and gly

This image is a public domain image, which means either that copyright has expired in the image or the copyright holder has waived their copyright. Alamy charges you a fee for access to the high resolution copy of the image.

This image could have imperfections as it’s either historical or reportage.

. Botany for agricultural students . Botany. SECRETIONS 285 A number of enzymes, such as diastase, invertase, maltase, zymase, and cytase, are involved in the digestion of the carbo- hydrates. Diastase, which is especially abundant in germinating seeds, changes starch into sugar. Invertase converts cane sugar into glucose and fructose, and maltase converts maltose into glucose. Zymase, well known as a secretion of the Yeast plant, converts sugar into alcohol and carbon dioxide. Cytase breaks cellulose into simpler compounds. The lipases digest the fats by changing them into fatty acids and glycerine, in which form the fats can be moved in the plant and consumed as food. For the glucosides there is also a group of enzymes. For amygdalin there is amygdalase, and for other glucosides certain other enzymes which decom- pose them. Although we know that en- zymes have much to do with the metabolic changes in plants, our knowledge of enzymes is comparatively meager. Inves- tigations on the kinds of en- zymes and their particular functions are much needed and are receiving much attention by plant chemists. Other secretions so far omitted from our list are the acids and the tannins. Malic acid, oxalic acid, citric add, tartaric acid, and a number of others, known as fruit acids, which function in determining the taste of fruits, are very important to man and assist in seed dissemination when they make the fruit more pleasing to the taste. Some of the organic acids often form compounds with minerals and form crystals. Crystals of cal- cium oxalate are quite common in plant cells. {Fig- 253.) The tannins are bitter astringent substances as any one who has tasted a green Persimmon well knows. They occur throughout plants, but are more abundant in the bark. Tannins harden the gelatine in skins, and before the chemists provided substitutes bark was extensively used in tanning leather. Due to their astringent and antiseptic properties, it is thought that they protect the plant aga