THE SEED 



11 



A better test is to weigh two or three ounces of seeds, and heat them 

 in a double boiler or in oil to prevent scorching. Weigh at intervals. If 

 ihcre is any loss of weight, to what is it due? 



l']xPERiMENT 11. Do SEEDS ABSORB WATER? — Soak a number of 

 hr-ans or grains of coi-n in water for 12 to 24 hours and compare with 

 dry ones. What difference do you notice ? To what cause is it due ? 



I'].\PERIMENT 12. lluVV UID WATER GET INTO THE SOAKED SEEDS? — 



Dry gently with a soft cloth some of the seeds used in the last experiment 

 and press them lightly to see if water comes out, and where. Place a num- 

 ber of dry seeds of different kinds — squash, bean, castor bean, quince, 

 etc. — in warm water and notice whether any bubbles of air form on them 

 and at what point. Examine with a lens and see if this point differs in any 

 way from the rest of the seed cover. Does it correspond with the point 

 from which water exuded in the soaked seeds? Could hard seeds like 

 the squash, castor bean, buckeye, and Brazil nut get water readily without 

 an opening somewhere in the coat ? 



EXPERIMBNT 13. To FIND OUT WHETHER WATER IS ABSORBED 



THROUGH THE SEED COATS. — Placc in moist sand or sawdust two rows 

 of beans as nearly as possible of the same size and weight, with the eye 

 pressed down to the substratum in one row and turned up in the other, so 

 that no moisture can enter through it. In the same way arrange two 

 rows of castor beans with the little end down in one row and uppermost 

 in the other. In the last set carefully break away the spongy mass near 

 the tip, without injuring the parts about it. Watch and see in which 

 rows water is absorbed most readily. What change takes place in the 

 spongy masses at the tips of those castor beans on 

 which they were left ? 



Experiment 14. Is 



THE rate of germina- 



tion AFFECTED BY THE PRESENCE OR ABSENCE OF 



openings ? — Seal up with wax or paraffin all the 

 openings of a number of air-dry peas or beans, and 

 leave an equal number of the same size and weight 

 untreated. Be careful that the sealing is absolutely 

 water-tight, since otherwise the experiment will 

 be worthless. Plant both sets and keep under like 

 conditions of soil, temperature, and moisture. Do 

 you see any difference in the rate of germination of 

 the two sets? 



Experiment 15. Do seeds exert force in 

 /* BSORBiNG WATER ? — Fill a commou six-ounce bot- 

 tle as full as it will hold with dry peas, beans, or 



Fig. 13. — Effect 

 of the expansion of 

 seeds due to absorp- 

 tion of water. 



