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



of apples tho not to so great an extent. How can we account for 

 these results? 



By referring to the figures in Table 2, it is seen that etherization 

 has very little effect in stimulating the CO 2 production of ash. It 

 is further noted that the ash tissue oxidized very slowly. It has also 

 been mentioned that some varieties of apples oxidize their tissue 

 more readily than others. Those which oxidize most are most easily 

 forced. 



The respiration curves of the Jonathan apple likewise indicate 

 that the increased amount of CO 2 produced as a result of treatments 

 varies with the advance of the season. When the stimulation was 

 greatest, the forcing of growth was most marked. 



It is quite possible that a given resting tissue may contain suf- 

 ficient soluble material to support growth as has been pointed out 

 by Johannsen. 1 Treatments in such cases might produce still more 

 sugar than was already present. However, the food must be usable 

 to be of value to the plant. Before it can be used at all, energy must 

 be made available. In order to furnish energy, material must be 

 oxidized and the oxidizing enzymes are responsible for this oxida- 

 tion process to a large extent. Again, not all food material is readily 

 oxidized. Certain substances, e. g., starch, must first be changed to 

 sugars before combustion occurs. In some plants, i. e., in those 

 where sugar is normally abundant, a rest period breaking agent 

 needs only to stimulate the oxidizing forces; while in others it be- 

 comes necessary to set in action those forces which convert insoluble 

 food into readily oxidizable and therefore energy yielding material, 

 as well as to stimulate the oxidizing agents themselves. 



The question may arise "Do these agents affect the enzymes 

 directly or, indirectly, by first influencing the general protoplasmic 

 organization?" The more growth there is, the greater the enzyme 

 activity, and hence it might be said that growth has already been 

 started as a result of the stimulus given by the rest period breaking 

 agent, and therefore enzyme activity naturally might be expected. 



There is no reason to suppose that the rest period breaking 

 agents single out and influence specific organisms of the protoplasm, 

 such as the enzymes. Many other portions of the "protoplasmic 

 makeup," a phrase which covers much that is unknown, might be 

 affected at the same time. We simply have an easy method of deter- 

 mining the enzyme activity but have no sure way of knowing whether 

 other parts of the protoplasm are not affected at the same time that 



1. Johannsen, W. Das Aetherverfahren beim Friihtreiben, etc. (Zweite 

 Anfl. Jena 1906). 



