UNIVERSITY OF CALIFORNIA PUBLICATIONS 



IN 



BOTANY 



Vol. 5, No. 16, pp. 451-455 April 3, 1919 



NOTES ON THE GERMINATION OF TOBACCO 



SEED III 



NOTE ON THE RELATION OF LIGHT AND DARKNESS TO 



GERMINATION 



BY 



T. HARPER GOODSPEED 



The recent paper of Honing^ reopens the question of the light 

 requirements for germination in Nicotiana. For a number of years 

 the writer has been convinced that the seed of the great majority of 

 species of Nicotiana would germinate in darkness and that the 

 numerous statements to the contrary were based upon experiments 

 not accurately controlled. An examination of the voluminous liter- 

 ature dealing with the influence of varying amounts of illumination 

 upon the germination of seeds leaves no doubt that temperature and 

 moisture effects are contributing factors in the results obtained, and 

 that the stage of maturity of the seed employed is a matter to be 

 carefully determined. Finally, when one considers that from the 

 strictly physiological point of view the influence of light upon germin- 

 ation corresponds to that of light upon growth phenomena in general 

 as an initiating stimulus and a source of energy, the need for the 

 most exact methods of experimentation is indicated. 



The following results dealing with the influence of light and 

 darkness upon the germination of five varieties of Nicotiana Tahacum 

 and five of N. riistica were obtained from experiments wliich are looked 

 upon as preliminary to a more thorough and better controlled investi- 

 gation. Since the results listed are so definite and since the larger 

 investigation contemplated must wait upon the completion of more 

 important matters, it seems well to present briefly the data at hand. 



»— . 1 Honing, J. A., The influence of light on the germination of the seeds of 



cr> different varieties of Nicotiana Tahacum, Bull. Deli Proefstat., December, 1916. 



QC 



