PHOTOPERIODIC CONTROL OF FLOWERING 



281 



Table III. Repromotion of Flowering in Indianapolis Yellow Chrysanthemum by 

 Far-Red-Radiant Energy Applied after Inhibition by Red 



" See text for description of stages of development. 



*■ Called relative stage of floral development in Tables IV to VII. 



In some other chrysanthemum varieties that are normally early 

 flowering it was possible by repromotion with far red to obtain flower 

 primordia that were just as far advanced as those of the unirradiated 

 controls (Table V). Plants of these varieties produced much more 

 advanced floral stages under the same inductive treatments than those 

 of the Indianapohs Yellow (Tables II and III). In the unirradiated 

 lots and in the lots exposed to far red the receptacle was completely 

 covered with florets on many of which the primordia of the individual 

 flower parts were recognizable. The 4-min red treatments, which were 

 highly inhibitory to flowering of Indianapolis Yellow (Table II), were 

 only moderately inhibitory to flowering of most of these varieties; 

 they prevented the production of floret primordia on the receptacle but 

 not the formation of the receptacle itself. 



Table IV. Repromotion of Floral Initiation in Indianapolis Yellow Chrysanthe- 

 mum by Far-Red-Radiant Energies Given Immediately after Red 



" Values are totals for 6 plants. See text for description of stages of development. 



