Page:First course in biology (IA firstcourseinbio00bailrich).pdf/135

Fig. 123.—To illustrate a Product of Respiration.

Fig. 124.—Respiration of Thick Roots.

Fig. 125.—To illustrate Transpiration.

(CO_{2}). 91. In a jar of germinating seeds (Fig. 123) place carefully a small dish of limewater and cover tightly. Put a similar dish in another jar of about the same air space. After a few hours compare the cloudiness or precipitate in the two vessels of limewater. 92. Or, place a growing plant in a deep covered jar away from the light, and after a few hours insert a lighted candle or splinter. 93. Or, perform a similar experiment with fresh roots of beets or turnips (Fig. 124) from which the leaves are mostly removed. In this case, the jar need not be kept dark; why? To test transpiration. 94. Cut a succulent shoot of any plant, thrust the end of it through a hole in a cork, and stand it in a small bottle of water. Invert over this a fruit jar, and observe that a mist soon accumulates on the inside of the glass. In time drops of water form. 95. The experiment may be varied as shown in Fig. 125. 96. Or, invert the fruit jar over an entire plant, as shown in Fig. 126, taking care to cover the soil with oiled paper or rubber cloth to prevent evaporation from the soil. 97. The test may also be made by placing the pot, properly protected, on bal-