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 of woody plants collected December 17 to 24 and etherized 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 development. 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 mollis, 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 forcing of bulbs and finds conflicting results. He states that the etherization of bulbs is not commercially practicable. Some unpublished data on the etherization of bulbs at the Cornell Station sustain this conclusion. 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 time it is first planted.

Effect On Rhubarb

Some positive results have been secured at the Vermont Agricultural Experiment Station 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.

4. It is wasted effort to etherize a plant that readily responds in growth to the normally favorable growth condition.

Bibliography

Howard, W. L., "Winter Rest-Period in Plants." Missouri Experiment Station, Research Bulletin No. 1 (1910). Johannsen, W., "Das Aether-verfahren beim Fruhtreiben mit besonderer Beriick-sichtigung der Fliedertreiberei." Jena, 1900. Zweite wesentlich erweiterte Auflage. Jena, 1906. Stuart, W., "The Role of Anesthetics and Other Agents in Plant-Forcing," Vermont Experiment Station, Bulletin No. 150 (1910). Lewis Knudson.