ETHERIZATION 



season advances toward the spring. Dormancy is 

 less stable in January than in November. This con- 

 dition holds true not only for woody plants but also 

 for bulbs and other herbaceous plants. 



Method of breaking the rest-period. 



The one method which has been largely employed 

 for forcing dormant plants into growth is the etheriza- 

 tion method. An air-tight chamber is provided, the 

 size depending on the quantity or size of the material 

 to be treated. The plants being placed in the chamber, 

 it is tightly sealed except for a small opening through 

 which ether may be introduced. Usually just below 

 this opening is placed a sponge on which the ether is 

 poured and then the opening is again sealed. If one 

 desires to etherize a few bulbs, a wide-mouth bottle of 

 two quarts capacity may be employed and the ether 

 added in a small vial and the bottle then tightly stop- 

 pered. Special etherizing chambers are described for 

 commercial work. The main desideratum is to have a 

 chamber that will not permit of leakage of the ether 

 vapor. The stopper must be securely fastened or 

 weighted down. 



Quantity of ether. The quantity of ether best 

 employed in forcing plants may vary with the nature 

 of the plant, the season of the year, and the tempera- 

 ture of the etherization chamber. In general, the quan- 

 tity to be added varies from 5 to 15 cubic centimeters 

 per cubic foot of space (10 cubic centimeters equal 

 about one-third fluid ounce) . Early in the rest-period at 

 60 F., one should use about 15 cubic centimeters per 

 cubic foot of space. In the middle of the rest-period, one 

 should employ less and the amount should be further 

 decreased toward the end of the rest-period. If the 

 relative humidity of the chamber is high, a slight 

 increase in the quantity of ether may be made. If 

 chloroform is used, the quantity should be one-fourth 

 to one-third of the quantity of ether recommended. 

 The following figures are from Stuart: 



TREATMENT RECOMMENDED FOR PLANTS AT DIFFERENT 



SEASONS 



Cubic centimeters per cubic foot 



ETHERIZATION 



1147 



Time of exposure. The time of exposure is also 

 variable, being of greater duration in the early part and 

 shorter in the latter part of the rest-period. In the 

 early rest-period, a long exposure is given, varying 

 from forty-^ight to seventy-two hours to even as much 

 as ninety-six hours. In case of long exposure, the prac- 

 tice is usually followed of making a forty-eight-hour 

 exposure, after which the plant is removed from the 

 etherization chamber for a day and then re-etherized 

 for another twenty-four-hour period. Toward the 

 middle and late rest-period, the time of exposure 

 may be shortened as well as the quantity of ether. 



The results. 



The effect of etherization is to shorten the rest- 

 period of the plant. Etherized plants come into bloom 

 earlier and may be forced at lower temperature than 

 unetherized plants. Howard found that seventy species 



73 



of woody plants collected December 17 to 24 and ether- 

 ized for forty-eight hours, opened their buds fully in 

 an average of 20.3 days, while the untreated plants 

 required an average of 28.1 days for the same develop- 

 ment. Many experiments have been made with lilacs 

 Jannvek states that lilacs etherized August 24 were in 

 bloom September 18. 



^ The following table compiled from results secured by 

 Stuart show conclusively the value of etherization 

 with lilacs: 



INFLUENCE OF ETHER AND CHLOROFORM ON LILACS 



In the foregoing table it is noted that treatment in 

 the middle of December resulted in no beneficial effect. 

 The plants at the time were in the middle rest-period, 

 when growth-response requires no strong stimulation 

 outside of normal growth conditions. 



In general it may be stated that lilacs if etherized 

 before December 1 will respond markedly to the 

 influence of etherization. General results show that 

 etherized lilacs blossom in seventeen to twenty-five 

 days. The saving in time may be eight to twenty 

 days. 



Favorable results have been secured with flowering 

 shrubs. Positive results have been reported frequently 

 for Azalea moUis, for Viburnum and Astilbe. Negative 

 or slight results have been reported for Deutzia gracilis, 

 Prunus triloba, roses, and Spiraea prunifolia. Similar 

 results have been reported for lily-of-the-valley. 



The method of action of the ether is not understood 

 and any discussion of the subject is yet hypothetical. 



Etherization of bulbs. 



On the forcing of bulbs the evidence is unsatisfactory. 

 At the Cornell Station, positive results were reported 

 (see Bailey, "Cyclopedia of Agriculture," Vol. II: 29), 

 but more recently Stuart has reinvestigated the for- 

 cing of bulbs and finds conflicting results. He states 

 that the etherization of bulbs is not commercially 

 practicable. Some unpublished data on the etheriza- 

 tion of bulbs at the Cornell Station sustain this con- 

 clusion. Theoretically, those results are to be expected 

 because the bulbs in practice are gathered in the late 

 spring or early summer and then stored for months. 

 After planting, the bulb is allowed to remain in a cold- 

 frame for several months so that when brought into 

 forcing conditions it is well over the rest-period and, 

 indeed, has probably passed through its period by the 

 tune it is first planted. 



Effect on rhubarb. Some positive results have been 

 secured at the Vermont Agricultural Experiment Sta- 

 tion with etherization of rhubarb. Different lots of 

 rhubarb were etherized on December 9, January 9 

 and February 24. The first gave an increase over the 

 control of 34.4 per cent, the second 89.7 per cent and 

 the third 5.7 per cent. 



General conclusions. Certain general rules may be 

 applied to the practice of etherization: 



1. Etherization shortens the rest-period. 



2. The more resistant a dormant plant is in growth- 

 response to favorable environmental conditions, the 

 greater will be the advantage of etherization. 



3. Etherization becomes of less value as the end of 

 the rest-period is approached. 



