GERMINATION OF SEED AS AFFECTED BY SULFURIC ACID TREATMENT 319 



hastening and increasing germination of this seed should be of great 

 importance to certain sections of the country. 



The results obtained by treating sweet clover seed (Mclilotus alba) with 

 concentrated sulfuric acid (sp. gr. 1.84) are given in Table 14. This seed 

 was grown in central Illinois in 1910 and was handled in small quantity in 

 an experiment, having, therefore, the most favorable conditions for curing 

 and for drying out thoroughly. The check tests gave an average germi- 

 nation of only 4.5 per cent. Treatment with concentrated sulfuric acid 

 for 25, 60, and 120 minutes resulted in germinations of 98 per cent, 99 per 

 cent, and 99 per cent, respectively. These percentages were raised to 100 

 per cent, 99 per cent, and 100 per cent, respectively, by treating the six 

 seeds not germinating after 22 days, in tests 3, 4, and 8, with acid for 30 

 minutes more and again placing them in the germinator for 4 days. 

 The seeds not germinated in the checks, Nos. i and 2, after 22 days 

 were taken from between the moist blotters and treated immediately 

 with concentrated sulfuric acid (sp. gr. 1.84) for 30 minutes. At the 

 end of 4 days after these were again placed in the germinator, 182 of 

 the 1 88 seeds treated were germinated, and at the end of 17 days 183 

 were germinated, while 5 yet remained ungerminated but apparently 

 alive. No further tests were made with these. 



The seed coats of this lot of seed were somewhat injured by the 1 2o-minute 

 treatment, being eaten through in places. Perfect germination took place, 

 however, in these cases. In this connection, H. N. Vinall, of the Office 

 of Forage Crop Investigations of the United States Department of 

 Agriculture, writes concerning some other lots of seed: " You will notice 

 that above 30 minutes the seed is pretty badly injured, and our germi- 

 nations show that the 15 -minute treatment gave the strongest germinations 

 in most cases. I am running a duplicate set of seed in which the seed 

 treated 30 minutes is giving the best results. The seed used had close to 

 50 per cent of hard seed in it. The results indicate that farmers will have 

 to be cautioned very strongly against handling the sulfuric acid treatment 

 loosely, as it appears the seed can be very readily injured by so doing." 



In order to test the effect of drying out of the seed after treatment with 

 sulfuric acid and washing with water, two samples treated with acid for 

 one hour were allowed to dry out thoroughly in a warm place for several 

 days before they were placed in the germinator. In Table 14 it is seen 

 that at the end of 4 days 98 per cent had germinated in one case and 96 

 per cent in the other, and after 6 days 99 per cent of the first sample 

 had germinated. This result is in accord with those obtained for red 

 clover, where the beneficial effects of acid treatment of hard seed still 

 obtain after the drying of the seed subsequent to treatment with acid 

 and washing with water. 



