Changes of Voluvie in Dry Seeds and Water. 179* 



Summary. 



Marked changes of the total vokime are shown when dry- 

 seeds absorb water. 



If the seed coat wrinkles, there is first an expansion, then a. 

 contraction, and then a final rise which is due to the production 

 of gas in the seed. The changes are not the result of alterations 

 of temperature. The wrinkling is due to unequally rapid ab- 

 sorption, partial vacuums forming under the wrinkles, whichi 

 hasten the indrawal of water. If the seed coat does not wrinkle 

 there is no preliminary expansion, and the contraction is due 

 as in gelatine to the compression of the absorbed water. 



Using similar methods as with the seeds, the contraction ob- 

 tained with gelatine indicated a pressure of 20 atmospheres, but 

 with seeds as much as 50 to 120 atmospheres pressure was in- 

 dicated. This may be due partly to the greater imbibition pres- 

 sure of organised cellulose as compared with gelatine, and partly 

 to the influence of solutes increasing the internal pressure of 

 the water within the seeds. 



