. Botany for agricultural students . Botany. ELABORATION OF FOODS INTO PLANT STRUCTURES 97 is inserted, the temperature of the enclosed air may be raised 10° C. and sometimes 20° C. by the heat of res- piration; and the oxygen of the enclosed air will usually be so nearly used up that the flame of a burning match or splinter is extinguished when inserted into the jar. (Fig. 92.) To demonstrate the ac- cumulation of carbon dioxide, one may pour lime water into the jar where the seeds are germinating, in which case the calcium hydroxide of the lime water unites with the carbon dioxide of the enc
. Botany for agricultural students . Botany. ELABORATION OF FOODS INTO PLANT STRUCTURES 97 is inserted, the temperature of the enclosed air may be raised 10° C. and sometimes 20° C. by the heat of res- piration; and the oxygen of the enclosed air will usually be so nearly used up that the flame of a burning match or splinter is extinguished when inserted into the jar. (Fig. 92.) To demonstrate the ac- cumulation of carbon dioxide, one may pour lime water into the jar where the seeds are germinating, in which case the calcium hydroxide of the lime water unites with the carbon dioxide of the enclosed air, forming calcium carbonate which is insoluble and when abundant gives the solution a milky appearance. Since the amount of carbon dioxide in ordinary air is not sufficient to give a perceptible precipitate, the milky ap- pearance, therefore, indicates that much carbon dioxide has been added to the enclosed air. Again, the carbon dioxide liberated in germination can be quite accurately measured by drawing the air from over germinat ng seeds through a solution of potassium hydroxide, where the carbon dioxide is caught and its weight calculated from the increased weight of the solution. However, this involves careful weighing as well as see- ing to it that the carbon dioxide already present in the air is removed before the air enters the germinator, and that the increased weight of the potassium hy- droxide is not partly due to added mois- ture. This method discloses that many cubic centimeters of carbon dioxide may be liberated by a small quantity of ger- minating seeds, as shown by the experi- ment in which 3 Beans with a dry weight. A B Fig. 92. — A simple ex- periment to demonstrate that heat is produced by germinating seeds. The bottle A contains germi- nating seeds, while the bottle B contains only moist cotton. The higher temperature, commonly shown by the thermometer in bottle A, demonstrates that germination is ac- companied by the pro- duction of heat. If t
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectbotany, bookyear1919
