312 



BOTANICAL GAZETTE 



[OCTOBER 



from 



potassium 



experiments 

 from coat < 



performed as follows. The seeds freed 



in water at o° C. for 12 hours were placed in 30 cc. distilling flask 



bearing about 20 cc. of distilled water. 



main 



mm 



ling flask was sealed off just above the side neck, and the side neck 

 reduced to a capillary tube at one region. A Geryk air pump 

 (capable of exhaustion to less than o . 1 

 drying system with great water-absorbing capacity, was attached 

 to the side neck and the flask exhausted. The flask was then placed 

 under water at 35 C. for one-half hour and the exhaustion con- 

 tinued. During the process the water generally boiled down to 5 



apillary 



While 



still maintaining 

 fully sealed off. 



will 



experiments 



more 



used in each culture. The 

 0.5 cm. column of distilled 

 darkness at a temperature 



experiments 



in 



The cultures were run in total 

 C. for 21 days. 



TABLE XIV 



Length of the seedlings in vacuo 



I 



II 



40 mm. 



35 mm. 



3° 



35 



3° 



35 



3° 



40 



40 



40 



25 



30 



25 



30 



25 



30 



32 



30 



25 



15 



Av. length . . 30 mm. 



32 mm. 



Length of the seedlings in full air pressure 



I 



70 mm 



60 



60 



5° 



50 



45 



45 

 40 



40 



40 



50 mm 



II 



70 mm 



60 



60 



60 



60 



55 



55 



50 



5° 

 50 



57 mm 



The imbibed embryo in the intact seed is approximately 2 . 5 mm. 

 long, so that the total elongation in the vacuum cultures equals 



