CHANGES ACCOMPANYING BREAKING OF REST PERIOD 9 



that every rest period can be broken since it depends upon regen- 

 eration of fermentative activity." He pointed out that a combina- 

 tion of high temperature and humidity favor fermentation; and he 

 thought it probable that the influences of ether could be traced to 

 this factor. He, however, made no direct experiments to prove his 

 statements. 



In this connection the statement of Fisher 1 is of interest. He 

 claimed that the resting buds of trees cannot be made to grow until 

 a certain minimum of the insoluble starch has been changed "to 

 easily respired and therefore energy yielding material." Johannsen 

 and Pfeffer, however, did not seem to think that the presence of 

 sugar was the determining factor. 



Gerrassimow 2 found that ether caused increased growth of 

 Spirogyra due to a stimulation of the cell nucleus. Latham 3 found 

 an increased economy in the metabolism after increased growth of 

 chloroformed fungi. According to Butkewitsch 4 ether vapor dis- 

 solves starch in the leaves. Lepeschkin 5 found that the osmotic 

 pressure of Spirogyra cells which remained in .05 per cent to 1 per 

 cent chloroform, or in 2.5 per cent ether solution for some time was 

 increased by 0.1 to 0.5 atmospheres. Zaleski 6 showed that etheriza- 

 tion increased the protein regeneration in the cotyledon of Lupinus 

 seedlings, diminishing the loss of glucose and causing a greater move- 

 ment from endosperm into the growing plant. 



NORMAL ACTIVITIES OF RESTING PARTS 



By first considering the normal physiological behavior of rest- 

 ing parts in plants, the later discussion of "abnormal" physiological 

 processes, such as those produced by the various means used to 

 break the rest period, will be better understood. 



Plants or plant parts in a state of "rest" are by no means inac- 

 tive. Cuttings of hardwood plants made in winter, form callus 

 tissue even tho the buds are incapable of growing. The reserve sub- 

 stances in trees undergo very extensive changes during the course of 



1. Fisher, A. Beitrage zur Physiologic der Holzgewachse, Jahrb. f. 

 wiss. Bot. (1891) 22, pp. 60-73. 



2. Gerrassimow, j. Aether-Kulturen von Spirogyra. Flora 94, pp. 16-26. 



3. Latham, Marion E. Stimulation of Sterigmatocystis by Chloroform. 

 Bui. Torrey Bot. Club 32, pp. 337-351. 



4. Butkewitsch, W. Upon the Occurrence and Function of Proteolytic 

 Enzymes in Germinating Seeds. Ber. d. d. Bot. Ges. 18 (1900) pp. 358-364. 



5. Lepeschkin, W. W. Effect of Anesthetics Upon Spirogyra. Ber. d. d. 

 Bot. Ges. (1911) 29, p. 355. 



6. Zaleski. Zur Aetherwirkung auf die Stoffumwandlung in den Pflanzen. 

 Ber. d. d. Bot. Ges. 28 (1911) pp. 292-296. 



