[Vor.. 2 



530 



ANNALS OF THE MISSOURI BOTANICAL GARDEN 



remaining practically normal 



doubt still continued. It 

 hether such transpirati 



sed lower conductivity 



readings, due to the consequent absorption of electrolytes, than 

 would have been the case had there been no, or only slight, 

 transpiration, as in the cases where the tops were removed. 

 The roots in all the cultures remained turgid and practically 



TABLE II 



EFFECTS OF ILLUMINATING GAS ON THE EXOSMOSIS FROM THE ROOTS OF 



PLANTS UNDER VARIOUS CONDITIONS 



Culture 





no. 



Treatment 



1 and 2 



3 



4 



5 



Controls in dist. H 2 0, 

 no gas treatment. 

 Tops cut off immedi- 

 ately after placing 

 roots in dist. H2O . . . . 



Illuminating gas 1 hr.; 

 roots in tumbler. Tops 

 not cut off 



Illuminating gas 1 hr.; 

 roots in tumbler. Tops 

 cut off immediately 

 after exposure 



Illuminating gas 1 hr. ; 

 roots in tumbler. Tops 

 cut off just before ex- 

 posure 



Interval in 

 dist. H 2 



before first 

 reading 



Conductivity Readings 



After 



first 



interval 



10 hrs. 



1 hr., 

 17 min 



1 hr., 

 23 min 



33.6 



18.4 



23.4 



1 hr., 

 28 min. 



18.6 



Increase! 

 over dist. 

 H2O after 



88 hrs. 



35. 8f 



50.7 



55.6 



54.5 



* Readings represent the values of x on the Wheatstone bridge, resistance in 



box being 9,110 ohms. 



t After 99 hours. . . 



J The average reading of the distilled water before roots were placed in it was 



approximately 6.0. 



normal 



The higher readings of the treated cultures who 



had been removed, over those of the untreated conti 

 o be considered as due to the effect of the illuminat 



8 



6 



posed to tl 

 in table n. 



;h in one case only part of the plants 

 ent. The results of this experiment a 



The results of ether vapor treatment for different periods 

 are seen in fig. 5. An interesting point in this connection is 

 the decline in the curves of the treated plants comparable in 



