Nov. i, 1920 Effect of Drying Disinfected Seed Wheat 215 



was possible, would notice at once the luxuriant growth of mycelium on 

 the injured seeds and its comparative rarity on the uninjured ones. He 

 might be inclined to ask whether the injury of the former samples was 

 not the result of fungous activities instead of action of formaldehyde 

 which might by its presence simply stimulate the growth of the mold. 

 This question is easily answered by disinfecting some of the dried, treated 

 seeds by a 10-minute dip into a 1 to 1,000 solution of mercuric chlorid 

 and germinating them on sterile blotters. The seedlings show the same 

 characteristic injury, but the percentages of germination are higher, 

 though not normal. This is because when they escape infection some 

 of the injured seeds succeed in germinating and produce weak plants. 

 These seeds, had they not been disinfected, would have been killed by the 

 invading fungus before the retarded root and plumule could emerge. The 

 extent of the development of this fungus on the various lots of germinat- 

 ing seeds serves as a fairly accurate index of the injury done to the seed by 

 the treatment. It is concluded from such experiments and many others 

 showing the same fact, which will be reported in detail in a subsequent 

 paper, that injury from drying after the formaldehyde treatment predis- 

 poses the seed to attack by molds, especially Rhizopus, the chemically 

 injured embryo being unable to resist infection. 



It is commonly believed that blotter germinations are worthless so far 

 as being an indication of the viability of seeds in soil. Therefore, along 

 with the blotter germinations summarized in Table I, occasional tests of 

 the stored seeds were made in pots of sandy loam soil in the greenhouse. 

 It was found that with the uninjured samples the soil germinations gave 

 the same results as those made at the same time in blotters. With injured 

 seeds they were lower, as was to be expected, for in the blotters all those 

 seeds were counted germinated which produced both root and plumule 

 even though these were stunted or deformed. In the soil such seedlings 

 would never reach the surface, and so the count of germinated plants 

 from injured seed lots would be lower. Consequently, the injury pro- 

 duced by drying the formaldehyde treated seeds appeared even more 

 strikingly in the soil and would more closely approximate actual field 

 results. This is shown in Table II. 



These figures do not indicate the full extent of the injury suffered 

 by the dried treated seed. Many of the seedlings from the injured 

 samples are short and spindling, while none of this sort are found in 

 the controls or in the samples which had been stored damp (PI. 37, A). 

 This same extreme injury was shown by the seeds stored dry in the 

 laboratory, but the figures are not included in Table II, because the 

 damp controls of both the untreated and the treated seed were destroyed 

 very quickly by the rapid development of Penicillium and Aspergillus 

 at that temperature. Plate 37, B, shows the seedlings produced by 

 these three seed lots injured by drying and the seedlings produced by 

 two of the controls. 



