312 Bulletin 312 



The resiilts obtained, as shown in this table, are practically the same as 

 those that were obtained in the first test, except, possibly, that the seeds 

 treated for the longer times were more injured in the second test. The 

 germination of the checks was about the same in each case, which would 

 indicate that " hard seeds " are not due altogether to conditions of storage, 

 but are probably due to inherent differences. Professor Williams recog- 

 nizes this in his letter quoted above, in which he states that 80 to 90 per 

 cent of the seed of some plants germinates promptly, while others give 

 only 5 to 10 per cent. 



Treatment of old seed 



The question arises, will the sulfuric acid treatment induce better 

 germination in old seeds of red clover? In order to test this, some lots 

 of old seed were procured and samples from these were treated with con- 

 centrated sulfuric acid for different lengths of time, after which their 

 germination was compared with untreated check samples from the same 

 lots. All the seed, owing to age, conditions of storage, or othenvise, had 

 lost largely in viability. The average germination of twenty samples 

 from these lots, receiving no treatment, was 4.05 per cent; for twenty 

 samples receiving sulfuric acid treatment for 10 minutes the average 

 germination was 4.45 per cent. 



Effect of drying after treatment 



When small lots of seed are being dealt with, as is often the case in 

 experimental work in which the yield of individual plants or of different 

 lines is kept separate, it is possible to plant, immediately after washing, 

 the seed that has been treated with acid. With larger lots, when the 

 seed is to be sown broadcast or in a seeder, the moist seed must be dried 

 before sowing. The question then arises, will the beneficial effects of 

 acid treatment of hard seed still be manifest after drying has taken place? 

 In order to determine this point, parts of several lots of seed were treated 

 with concentrated sulfuric acid for one hour. After thorough washing 

 the seeds were dried near a radiator for several days, as shown in Table 10, 

 and then germinated between blotters without further treatment. 



The results obtained from these tests are shown in Table 10. Lot I-2 

 showed a germination of 98.5 per cent after 5 days drying, as compared 

 with 96 per cent secured without drying and with 21 per cent in the check. 

 In a similar manner, all the other lots reported on in this table, after 

 drying four to six days (i. e., becoming thoroughly dry), germinated 

 practically a^ well as, or better than, the same lots did when drying out 

 did not intervene between acid treatment and the germination test. The 

 same is true for samples I-4-A and I-5-(A and B), in which cases 34 

 days intervened between the treatment and the test. In every case 



