1913] Goodspeed: Germination of Tobacco Seed 219 



Table 8 brings out more elearlj^ the relative amounts of ger- 

 mination of hybrid and parent seed on corresponding years. 



In the case of two and three year-old seed the higher per- 

 centage of germination for the hybrid seed as compared with the 

 seed of the parental N. Ta&acMm-varieties is marked, while in 

 one-year-old seed which involves the seed of F, hybrids the con- 

 trast is much less striking. Further tests are contemplated which 

 may throw some light on the significance of such results as these. 



VII. SUMMARY OF RESULTS 



The following summary of results is based upon the above 

 description of germination tests and others involving in all over 

 20,000 seeds produced from single plants of ten species and 

 varieties of Nicotiana and from single plants representing the 

 original hybrid seed and the F^ and Fo generations in the case 

 of two hybrids made between two N. Ta6acum-varieties. 



(1) The action of 80 per cent sulfuric acid upon tobacco seed 

 for lengths of time not over ten to twelve minutes increases 

 markedly the total amount of germination and in certain cases 

 increases rapidity of germination. 



(2) The action of concentrated sulfuric acid (sp. gr. 1.84) 

 for periods of time as short as one minute killed the seed used. 



(3) A markedly injurious effect of prolonged washing with 

 running water after sulfuric acid treatment was noted. 



