8 MASS. EXPERIMENT STATION BULLETIN 376 



storage temperatures on Easter lilies in relation to flowering and observed 

 that bulbs produced a greater number of blooms in the field when stored 

 at warm temperatures than at cool temperatures. Hosaka (5) observed 

 that subjecting bulbs of Lilium japonicum var. msulare for a period of 20 

 days to a temperature of 80° P., followed by a 40-day treatment at 55° 

 F., stimulated root development and bud formation. When bulbs were 

 held for 40 days during the rooting period at a temperature of 55° F., 

 budding and flowering were very irregular and the results inferior to 

 those obtained with a warm rooting temperature. 



Experiments with Lilium longiflorum giganteum, 

 Waltham, Mass. 1935-1937 



Bulbs were rooted under controlled temperature conditions and in the 

 greenhouse where temperatures were comparable to those used in com- 

 mercial culture. The temperature controls were especially constructed 

 cabinets containing approximately 20 cubic feet of space, with sides of 

 double glass arranged to provide a one-inch air space, thus increasing 

 insulation and admitting light to permit growth of plants. Splitwood 

 blinds shaded the cabinets and control instruments from direct rays of 

 the sun. Temperature was controlled by air thermostats of a bimetal 

 type with a double mercury-tilt switch. Refrigeration was supplied by 

 methyl chloride forced through coils hung from the top of the cabinets. An 

 electric strip heater supplied heat which was circulated with a small 

 electric fan. The temperature was controlled within a 3° differential when 

 operated within 30° of the outside air temperature. No humidity control 

 was provided, but pots of moist soil gave a variable relative humidity 

 between 30 and 60 percent which averaged higher at cooler temperatures. 



The controlled temperature cabinets used to root lily bulbs were op- 

 erated at 42°-45° F., 52°-55° F., 62°-65° F., 70°-72° F., and 80°-82° F. In 

 the greenhouse experiments, temperatures of 50°-52° F. at night and 55°- 

 56° F. during the day were used to provide a cool rooting condition; 

 while a night temperature of 60°-62° F. with a day temperature of 65°- 

 68° F. provided a warm temperature condition. The temperatures in the 

 greenhouses were regulated by thermostats. 



Lily bulbs of 7-9 and 8-10 inch size were used in the experiments. The 

 bulbs were allowed to remain in the cabinets and greenhouse rooting 

 temperatures for a period of approximately six weeks, after which they 

 were placed in a greenhouse and grown at a 60°-62° F. night temperature 

 and 65°-70° F. during the day. 



Root Growth. — Bulbs of Lilium longiflorum giganteum rooted much more 

 quickly at a temperature of 60°-70° F. than they did at 52°-55° F. This 

 difi^erence in root growth due to temperature treatments was noticeable 

 at the end of the six weeks rooting period and was still discernible at the 

 end of 70 days from the date temperature treatments were started. At 

 temperatures of 52°-5S° F. root growth was poorer than at 60°-70° F. Bulbs 

 did not root well at 80°-82° F. and the root systems developed by the 

 bulbs were comparable to those on bulbs rooted at temperatures of 52°-55° 

 F. The differences in rooting responses of the bulbs rooted at various 

 temperatures as observed 70 days and 98 days from the date treatments 

 were started are shown in Figure 1, A and B. 



