GERMINATION OF SEED AS AFFECTED BY SULFURIC ACID 



TREATMENT * 



Harry H. Love and Clyde E. Leighty 



The seed of many species of leguminous plants usually contains a 

 considerable amount of seed that germinates slowly or not at all. Such 

 seed is often referred to as " hard seed." Very frequently there is so 

 much of this hard seed present that germination tests, even when con- 

 tinued for three weeks, give results entirely misleading as to the viability 

 of the sample or lot of seed. When such seed is sown in the ordinary 

 way, a very poor stand of plants is usually secured. This is especially 

 true in dry seasons or in regions of light rainfall. In experimental work, 

 where the growth of every seed is important, the presence of hard seed 

 often brings the experiment to an untimely end. Some method, there- 

 fore, of obviating this difficulty should be of value both to farmers and to 

 those engaged in experimental work. 



It is the purpose of this paper to set forth a method of treatment for 

 hard, leguminous seed that will practically do away with delayed germina- 

 tion. This method was first discovered by one of the writers in 1906. 

 Some breeding work on red clover was being done, but it was found that 

 much of the seed germinated poorly. Examination of the seed and further 

 tests proved that the poor germination was due, without doubt, to the 

 presence of hard seed in the lines being used. Experiments were insti- 

 tuted in which the seed coat was pricked with a needle or burned with 

 a hot needle. It was found that when the seed coat was thus broken 

 immediate germination usually ensued. The seed was also treated with 

 many different chemical solutions in an effort to find one that would 

 bring about the result desired. Among these was sulfuric acid of various 

 strengths. As a result of these tests, the only chemical treatment that 

 hastened and increased germination to any marked degree was immersion 

 in concentrated sulfuric acid (sp. gr. 1.84) for a few minutes. The results 

 obtained by this treatment were so uniformly good that, for the benefit 

 of others who were experiencing the same difficulty with hard seed, it 

 was decided to bring together some results for publication. 



ACKNOWLEDGMENTS 



The writers desire at this time to acknowledge the kindness of Dr. 

 L. H. Smith and J. B. Park, of the Illinois Agricultural Experiment 



• Paper No. 24, Department of Plant-Breeding, Cornell University, Ithaca, N. Y. 



295 



