B. P. I.-94. B- I- E— '■'6. 



THE \ ITALITY AND fxEKMlNATlON OF SEEDS. 



INTRODUCTION. 



It has lonjr been known that tho conditions under which plants are 

 grown and the degree of maturity at the time of harvesting are fac- 

 tors which phiy an important part in the life of seeds. But, granting 

 that seeds are of strong vitality at the time of harvesting, there 

 remain to ho considered the methods of gathering and curing, the 

 water content of the sec^l at the time of storing, the methods of stor- 

 age, the humidity and temi)erature of the surrounding atmosphere, 

 the composition of the seed, the nature of the seed coats, activities 

 within the cells, and numerous other factors which phw important 

 parts in the life of the seed. 



The conditions necessary for the successful germination of a seed of 

 good vitalit}' and the chemical transformations accompanying these 

 earl}' stages of development have received considerable attention from 

 numerous investigators. These changes and conditions are fairlj^ well 

 understood for many of our common seeds. However, several impor- 

 tant facts still remain unexplained, and our knowledge will not be 

 complete until each and every species has been carefully studied. 



On the other hand, the conditions influencing the vitality of seeds as 

 commercially handled are but little understood and have been almost 

 wholl}' neglected in research work. Likewise, but little attention has 

 been given to the complex chemical and physical changes wdiich take 

 place in mature seed during the slow process of devitalization. It was 

 in order to determine some of these factors that the work descril)ed in 

 these pages was begun, and the results are thus of considerable practi- 

 cal value as well as of scientitic importance. The present paper treats 

 chie% of the conditions influencing the vitality and germination of 

 seeds when sul)jected to such methods of treatment as are generallj^ 

 met with in the ordinary handling of seed. Particular attention has 

 been given to the effect of climate, moisture, and temperature on 

 vitality, supplemented with a discussion of the changes taking place 

 in mature seeds, especially the respiratory activities and the part 



plaj'ed by enzymes. 



9 



