i 9 2i] PACK—JUNIPERUS 59 



higher temperatures until germination has started. If these seeds 

 are given sufficient time they will germinate, even at o=t= i° C. 



n. Subsequent to after-ripening and germination at 5 C, the 

 best temperature for seedling development is 15 C. 



12. The development of chlorophyll in the juniper seed and 

 seedling was found to be independent of light, but conditioned 

 by the temperature range. Seedlings grown at temperatures of 

 o±i°C. or 30 C. never developed chlorophyll. Anthocyanin 

 development in seedlings seems to depend upon relative tempera- 

 ture and carbohydrate supply. 



13. A more complete chemical analysis of these seeds at differ- 

 ent stages of development will be given in a later paper. 



Acknowledgments are due Dr. William Crocker and Dr. S. H. 

 Eckerson, under whose direction and criticism this work was 

 carried on. 



A. and M. College 

 College Station, Texas 



LITERATURE CITED 



1. Appleman, C. O., Relation of oxidases and catalase to respiration in 

 plants. Amer. Jour. Bot. 3:223-233. 1916. 



2. Atwood, W. M., A physiological study of the germination of Avena falua. 

 Bot. Gaz. 57:386-414. 1914. 



3. Behrens, W., Uber die Beeinflussung der Keimfahigkeit gevvisser Samen 

 durch Narkose und Verwundung. Bericht. Grossh. Bad. Landw. Versuch. 

 Augustenberg. S. 60-64. 1906. 



4. Brtjyning, J. F., On the use of hot water for forcing germination of hard 

 coated seeds. Jour. Landw. 41:86. 1896. 



5. Crocker, W., Mechanics of dormancy. Amer. Jour. Bot. 3:99-120. 1916. 



6. Crocker, W., and Harrington, G. T., Catalase and oxidase content of 

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7. Czapek, F., Biochemie der Pflanzen. 1:710. Jena. 1913. 



8. Davis, W. E., and Rose, R. C, The effect of external conditions upon 

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 1912. 



9. Dutcher, R. Adams, Vitamine studies. Jour. Biol. Chem. 36:63-72. 

 1918. 



10. Eckerson, S. H., A physiological and chemical study of after-ripening. 

 Bot. Gaz. 55:286-299. 1913. 



