Livingston : Chemical stimulation of a green alga 



13 



12. Hydrogen nitrate, nitric acid (HNO3). — This body kills 

 the plant at a concentration of 5;// 10,000, Palmella is produced 



from njio.ooo to 6///ioo,ooo, sometimes even in 3;//ioo,ooo. 

 Acceleration of zoospore production is exhibited from ///i 00,000 



to 6;//i 00,000 or 3;//! 00,000, in certain cases, and below the last- 

 named strength, at least at ;//i 00,000, the alga appears normal. 

 (Seey?^. /J, which shows palmella produced from filaments in a 



solution of 6;//ioo,ooo concentration.) 



12 



s 



I 



13 



» 



Figure 12. Palmella and some filaments changing to palmella, from ;//i,ooo,cx>o 



CuSO^. 



Figure 13. Palmella from 6;//loo,ooo IINO3. 



ij. Hydrogen sulfate, sulfuric acid (HgSOJ. 



This follows 



nitric acid very closely. There seems to be here sometimes a 

 tendency for the palmella range to extend downward so to include 



i 



n/ 100,000, but it was impossible to establish this for a certainty in 

 all series. If it be so, it of course means that the sulfate is some- 

 what more active than the nitrate, and that the action in this case Is 



