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



100 C. for a few minutes. This upon being allowed to act upon the 

 starch paste showed no color reaction with the iodine. The tests 

 showed that the agents which are known to break the rest period 

 increased the diastatic enzyme activity of the dormant tissue. 



The extent of the activity varied considerably, depending upon 

 the species of dormant twigs used, the rest breaking agent employed, 

 time of treatment, etc. In general the diastatic activity following 

 treatment was found to agree very well with the extent to which the 

 treatments broke the rest period, or produced early growth. 



The test for the presence of active proteolytic enzymes in the 

 tissue of dormant twigs was determined by finding to what extent 

 such woody tissue, after being treated with rest period breaking 

 agents, would liquify hard gelatin. The results of the test showed 

 very clearly that the ether treatment caused a very great amount of 

 proteolytic enzyme activity. 



A few tests were made to determine whether the fat splitting 

 enzymes were affected by agents which break the rest period. Cor- 

 tex from treated material was allowed to act upon castor oil emul- 

 sion at 35 C. for from ten to twenty-four hours. At intervals the 

 liquid was tested for acidity by using neutral litmus, or a few drops 

 of phenolpthalein, and adding NaOH solution drop by drop until 

 the red color appeared. In all cases tried, the etherized material 

 was the most active in producing fatty acids. 



Evidences of the activity of oxidizing enzymes as influenced 

 by rest period breaking agents were frequently observed thruout 

 the season during the progress of the respiration experiments. A 

 special experiment with treated apple twig cortex in late winter 

 showed that etherization of dormant plants may greatly arouse the 

 activity of the oxidizing ferments. These tests were dependent 

 upon color changes of tissue in the open air, after being exposed to 

 treatments. 



The sugar content of treated and untreated twigs was deter 

 mined by testing water extract from the twig cortex with Fehling's 

 solution, according to the Agricultural Chemists' official method. 

 The results of the sugar test substantiated those obtained in connec- 

 tion with the enzyme activity, thus indicating that treatments sue h 

 as etherization, warm water bath, alcohol bath, hydrochloric acid 

 bath, drying, mechanical injury, etc., when applied during the early 

 winter increase the amount of readily soluble reducing sugars within 

 twenty-four hours after applications are made. If treatments are 

 given somewhat later in the season, the agents have little or no 

 effect on increasing the amount of sugar. If delayed until very late 



