EXERCISE IV 



ABSORPTION OF WATER BY SEEDS 



Material. Seeds of beans, peas, corn, canna, honey locust, 

 and field beans. 



Apparatus. Scale, 250-cc. graduated cylinder, 100-cc. wide- 

 mouthed bottles. 



1. To determine volume. Partly fill the graduated cylinder with 

 water and read the height to which the column of water stands. 

 Now count out fifty seeds of the bean, pea, and corn and drop 

 each lot separately into the water in the cylinder. Remove the air 

 bubbles each time by slightly shaking the cylinder. The height 

 of the column of water is again read and the difference in the two 

 readings indicates the volume of each sample in cubic centi- 

 meters. How does this vary wth the different seeds ? Explain. 



2. To determine the amount of water absorbed by seeds. Weigh 

 fifty seeds of peas, beans, and corn and tabulate the weight 

 of each lot. Place the seeds in a wide-mouthed bottle of about 

 100 cc. and cover them with water. Allow them to stand for 

 twenty-four hours in a room where the temperature is about 

 70 F. The following day remove the seeds, wipe dry, and 

 weigh. Tabulate your results. Discuss. Allow the same seeds 

 to soak in water for another day and note whether there has 

 been any increase in weight. At what time was the greatest 

 amount of water taken up ? Discuss. 



3. Now take fifty more seeds, the same as in 2, and treat in 

 the same manner, only place them in a temperature of about 

 40 F. Note your results and explain. 



4. Secure fifty seeds of the canna or honey locust and treat 

 them in the same manner as in 1 and 2. Note the difference, if 

 any, and discuss. How do you account for the change ? 



5. Weigh out two samples of field beans and place one lot 

 in water and the second sample in damp sand. Weigh each lot 

 the two following days and compute the per cent of water 

 absorbed by each. 



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