3 8o 



BOTANICAL GAZETTE [may 



hydroxid. One cubic centimeter of this solution was added to three 

 different liquids: I, liquid from culture 6 days old; II, the same 

 liquid after having been boiled 10 minutes; III, distilled water. 

 When examined 24 hours later I was pronounced rose-red, while II 

 and III were merely faint pink; which indicates that leuco-rosolic 

 acid is capable of showing the action of those oxidizing enzymes. 

 Attempts were made to use ferrous ammonium sulfate and potas- 

 sium iodid as indicators of the oxidizing powers of plants by putting 

 small amounts into cultures containing living plants. Ferrous ammo- 

 nium sulfate was, in the space of time of the experiment, oxidized 

 by mere contact with the atmospheric oxygen, and was therefore 

 discarded as an indicator. Potassium iodid was not oxidized to free 

 iodin, as Raciborski has also found. 33 



EFFECT OF DIFFERENT CONDITIONS IN THE SOLUTIONS UPON THE 



alkalinity 



ACTIVITY OF THE ENZYMES 



Mention has previously been made of instances where th 

 in oxidation appeared to be partly due to the acidity or 

 of the solution used as a culture liquid. In such cases the grou » 

 of the plant roots was affected whenever the alkalinity or acidity *as 

 very pronounced. The effect is the more harmful when young see^ 

 lings are put into such solutions, because at the beginning ;o_ 

 experiment, when the plants are very tender, the acidity or alka unsj 

 is greatest and gradually diminishes during the progress of- the exp^ 

 ment. In investigating the effect of acid or alkaline condltl ° nS . * g at 

 the culture media, instead of using either alkaline or acid solu 10^ 

 the start, a method was used whereby the originally neutral so ^ ^ 

 became acid or alkaline as a result of the selective a b sorptl °* s been 

 plant in withdrawing nutrients from the solution. 34 * ** rtheir 

 demonstrated by Kohn and Czapek 35 that fungi may ren ^ 

 culture media alkaline or acid as a result of their selective a so ^ ^ 

 whereby an acid or a basic radical is removed more rapid y ^ 

 radical to which it is linked. Reed 36 has observed a sum a 



33 Bull. Acad. Sci. Cracovie 1905:668. T g p e pt- 



34 See Cameron, Kept. U. S. Dept. Agr. 71:67- l 9° 2 '> Bur ' ! 

 Agric. Bulls. 30 and 41. 1905. 



35 Beitr. Chem. Phys. Path. 8:302. 1906. 



3 6 Annals of Botany 21 : 501. 1907. 









