22 THE VITALITY AND GEKMINATION OF SEEDS. 



while seed from the same lot stored at Ann Arbor germinated 93 per- 

 cent. The cabbage seed was injured nearly as much as the onion, the 

 sample from Mobile germinating only 8.5 per cent. The conditions 

 at Baton Rouge were slightly more favorable to the preservation of 

 vitality. The cabbage seed stored at the latter place germinated 22.5 

 per cent, while a like sample of seed stored at Ann Arbor germinated 

 86.5 per cent. The lettuce was much more resistant than either the 

 cabbage or the onion seed, but here, too, the injury was quite marked, 

 especially as shown by the retardation in germination. The conditions 

 at Mobile were also the most disastrous for the lettuce seed. During 

 the first 36 hours that the tests were in the germinating chamber none 

 of the lettuce seed from Mobile germinated, while the seed from the 

 corresponding sample from Ann Arbor germinated 67 per cent. The 

 final percentages of germination were 64 and 96.5 per cent, respectively, 

 for the seed from Mobile and Ann Arbor, showing a loss in vitality of 

 33.68 per cent in the seed stored at Mobile. Here it will be seen, as in 

 Table V, that the onion seed was most sensitive and the lettuce seed 

 most resistant to the unfavorable conditions. In the first tests shown 

 in Table V the average loss in vitality of the lettuce, cabbage, and 

 onion was 15.77, 43.56, and 74.10 per cent, respectively, while for the 

 last tests, as shown in the foregoing table, the losses in vitality of 

 similar samples of seed kept at Mobile were 33.68, 91.29, and 100 per 

 cent, respectively. The ratio is practically the same in both cases, the 

 loss in the cabbage seed being 2.7 times greater than that of the lettuce. 

 The foregoing data are sufficient to indicate that climatic influences 

 play a very important part in the life of seeds, and that the degree of 

 injury varies greatly in different places and likewise in different seeds. 

 Some seeds were practically worthless after an exposure of four or five 

 months in such places as Mobile, Baton Rouge, or San Juan, as shown 

 in Table I. After longer exposures, six or nine months, similar results 

 were obtained from all of the places to which seeds were sent. Many 

 of the seeds were killed, as shown in Table II. The conditions at 

 Mobile were fatal to all of the seeds; that is, the seeds were worthless 

 so far as the gardener is concerned. 



CAUSES OF THE LOSSES IN VITALITY IN DIFFERENT CLIMATES. 



Having shown that seeds lose their vitality much sooner in some 

 localities than in others, the question naturally arises, "Why this 

 loss in vitality?" Unfortunately only two of the places where seeds 

 were stored, Mobile and San Juan, have Weather Bureau stations which 

 are equipped for making complete observations of the meteorological 

 conditions. It has been observed, however, that there is a very close 

 relationship between the precipitation and the loss in vitality in seeds; 

 that is to say, in a measure the loss in vitality is directly proportional 

 to the amount of rainfall. This deterioration is more apparent as the 



