3 82 



BOTANICAL GAZETTE 



[may 



nium sulfate. Neither is it probable that the sulfate radical is the 

 depressing factor, since calcium sulfate compares favorably with 

 calcium nitrate in its effect upon oxidation. The more favorable effect 

 of no. 2 in Table X upon oxidation over nos. 3 and 4 is probably to 

 be attributed to the presence of nitrate, which likewise appears to be 

 responsible for a material increase in growth. 



The greater oxidation accomplished by no. 9 over no. 10 is probably 

 not to be attributed to the presence of CI, but to the smaller amount of 



K present in no. 9. 



On the whole it appears that while oxidation is affected to a certain 

 extent by conditions of acidity or alkalinity arising in the culture 

 medium, it is more materially affected by the specific action of the 

 salts and their elements in the solution. 



The direct effect of acid and alkaline conditions upon the activity 

 of peroxidase was investigated by the following experiment in w 

 alcoholic aloin was used as the indicator. A liquid showing strong 

 peroxidase action was taken from a pan in which several hundred 

 7-day-old wheat seedlings were growing. Various amounts of «/5° 

 HC1 and w/50 NaOH were added to a set of tubes each containing 

 io cc of the culture liquid and i cc of alcoholic aloin solution adde 

 at 3 p. m., January 13. The following table shows the amount 

 acid or alkali added in each tube, and gives the record of the colors 

 observed at n a. m. the following day. 



hich 



TABLE XI 



Effect of acid and alkaline conditions upon the activity of peroxidase in the a se 



of plants. 



No. 



I 



2 



3 



4 



5 

 6 



7 

 8 



9 

 10 



11 



12 



o cc culture liquid + o.i cc n/50 HC1 



.< +a2 



( 



4 

 I 

 I 

 I 

 i 

 I 



I 



I 

 I 



it 



a 

 a 

 U 

 a 

 II 

 II 

 II 

 II 

 a 



u 

 a 

 it 



<< 

 it 

 11 



a 



a 



<< 





it 



it 



it 



n/50 NaOH 



+ 0.5 

 -f-0.7 



+ 1 .0 



+ 0.1 



+ 0.2 

 + 0.5 

 + 0.7 



+ 1.0 . 



neutral to litmus solution 

 a a tt <* 



it 

 a 

 it 

 it 



it 

 it 

 fl 



Color observed at end 

 of 20 hours 



faint pink 



ii 



no change 



it 



a 



a 



it 



red 



wine-red 

 deep wine-red 



a 



a 



a 



a 

 a 



deep pink 

 a » 



