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



tion in different species of dormant twigs; and to test the effects of 

 the same dose of ether on CO 2 production of dormant apple twigs 

 at different times during the season. 



Special apparatus was designed for conducting the respiration 

 tests. There were six chambers consisting of tall glass jars, each 

 with a capacity of 2.5 liters. These contained the twigs to be tested. 

 The jars were connected on one side with a KOH tube and on the 

 other with a CaCl 2 tube and Geissler bulbs containing a saturated 

 solution of KOH. The six jars were inclosed in a large double- 

 walled galvanized iron chamber with water jacket. The air was 

 drawn thru the tubes, jars and bulbs at the rate of three liters per 

 hour. The KOH freed the ingoing air of all CO 2 and the outgoing 

 air passing thru the CaCl 2 tube gave up all its moisture and the 

 KOH in the Geissler bulbs absorbed the CO 2 given off by the twigs, 

 while any moisture evaporating from the bulbs was retained by the 

 CaCl 2 tube next to the aspirator bottle. A self-recording thermo- 

 graph inside the large chamber registered between 15 and 18 C. 

 thruout the tests. 



A set of twigs was frozen at -15 to -19 C., another dried at a 

 temperature of 26 to 31 C., and a third placed in a humidor at room 

 temperature. After sixty hours all were placed in the respiration 

 chambers. During the first day the froxen twigs produced four 

 times as much CO 2 per hour, per 100 grams of tw T igs, and the dried 

 twigs three times as much as the twigs that had been kept moist to 

 check the results. 



Dormant apple, ash, oak and mulberry twigs were exposed to 

 ether used at the rate of one-half cc. per liter of space, for twenty- 

 four hours. These with control twigs were then placed in respiration 

 chambers. The normal respiration was found to be greatest in the 

 mulberry, and least in apple and ash. Etherization caused in- 

 creased CO 2 production in all cases, but it was greatest in the apple. 

 When placed in the greenhouse those species in which CO 2 production 

 was stimulated most by etherization began growing earlier than 

 similar untreated twigs. Where the treatment failed to stimulate 

 CO 2 production as with oak and ash the growth was not materi- 

 ally hastened. --vl '<'; 



Apple twigs were etherized m October, November, January, 

 February and March. In all cases from the earliest to the latest 

 date the respiration was markedly increased during the first three 

 days. In October, November and January this increase continued 

 after the third day while later in the season in February and March 

 the respiration actually decreased very greatly (as compared with 

 the control twigs) beginning with the fourth day after treatment. 



