22 MISSOURI AGR. EXP. STA. RESEARCH BULLETIN NO. 21 



Agents Employed. The agents employed to break the rest 

 period were etherization, drying, warm water bath, alcohol bath, 

 hydrochloric acid bath, sodium nitrate spray, and mechanical injury. 

 The strength as well as the duration of the treatments are given in 

 the tables. Etherization was carried out as previously described. 



Suitable checks were used in all cases. For example, if treated 

 twigs were being bathed in alcohol, the untreated or check twigs 

 were immersed in pure water during the same period. This was done 

 to equalize as far as possible any effect that exclusion of free oxygen 

 from the twigs might have on the enzyme activity of the tissue. 

 Similar precautions were taken in case of checks for other forms of 

 treatment. 



The enzyme activity was determined either immediately after 

 the close of the period of application of the treatment, or after an 

 interval of one or more days. During this interval the twigs were 

 kept standing at room temperature in beakers containing about 50 

 cc. of tap water. 



Preparation of Material. The outer fleshy parts only were used 

 to determine the enzyme activity of the twigs. This fleshy portion, 

 including the cortex proper, the bast layer, the cambium and more 

 or less of the sap wood as well as the lateral and terminal buds, as 

 a matter of convenience, are listed in the table under the heading 

 of "cortex." The term is used very loosely. The buds alone would 

 have been best for the enzymatic tests, but it was very difficult to 

 obtain material of this kind in sufficient quantities. The hard, 

 woody part of twigs is very low in enzymic activity. Hence the 

 choice of the fleshy portions. 



The "cortex" was scraped from the twigs with a knife. The 

 shavings thus secured were then finely ground in a common kitchen 

 meat chopper. The chopper sheared the tissue into fine particles 

 but did not squeeze out the juice unless the material was very suc- 

 culent. The mass after grinding was very uniform thruout. 



When buds alone were used to determine the enzyme activity, 

 the entire buds together with about 3 to 5 cm. of the spurs on which 

 they grew were ground up. Several 5 gr. samples of each kind of 

 material were carefully weighed out and placed in glass vials. 



1. Diastatic Activity. The first test was for diastatic activity. 

 To each vial of the cortex was added 25 cc. of a 2 per cent potato 

 starch paste. The starch paste was made by adding 90 cc. of boiling 

 water to 2 gr. c. p. potato starch which had been wet with 10 cc. of 

 cold water. After cooling, 2 per cent toluene was added to this paste. 



