214 Journal of Agricultural Research vol. xx, no. 3 



The outstanding fact shown by these experiments is that all the seed 

 which was treated with the formaldehyde solution and then dried by 

 being allowed to stand open to the air was either killed or seriously 

 injured after three to six days, while that treated at the same time and 

 stored at the same temperatures, but kept damp by being sealed in 

 jars, was practically uninjured up to the time it was destroyed by molds. 

 Later experiments have shown that injury may appear in dry-stored 

 seeds in less than three days, depending on the manner of drying. The 

 dry controls maintained the original germination throughout, and the 

 wet ones did also until they were killed by the development of fungi in 

 the jars. It will be noticed that molds appeared more slowly in the 

 damp, treated seed than in the damp controls, giving evidence of the 

 fungicidal action of the formaldehyde remaining on the seed. The 

 reason for the more extreme injury in the lots stored at room temper- 

 ature and in the refrigerator compared with those in the greenhouse 

 will be discussed later. These percentages also show most strikingly 

 that the injury to dried seeds is cumulative and that there is no recovery. 

 This is borne out by all subsequent experiments and refutes the claim 

 of McAlpine (11) and Darnell-Smith and Carne (5) that there is a steady 

 improvement after the extreme injury which appears after a week or so. 



In addition to low germination percentages, the injured samples 

 showed a characteristic deformity and extreme retardation of the injured 

 seedlings. The earliest appearance of injury in the dried seeds was simply 

 a noticeable retardation of germination in the samples after being stored 

 three and six days, the plumules and roots never catching up with those 

 of the uninjured seedlings. The retardation became more extreme as 

 storage continued, with an ever-increasing number of short plants which 

 grew very slowly and resulted in stunted and misshapen plumules and 

 underdeveloped roots. After 10 days' storage all the seeds of the three 

 treated and dried lots were thus inhibited, so that upon germinating they 

 presented the appearance shown by those in Plate 36, A. The character- 

 istic deformity by which this extreme formaldehyde injury can always be 

 detected is the curving of the plumule as it emerges until it is sickle- 

 shaped (PI. 36, B). The growth of the sheath is inhibited so that it 

 never grows more than a few millimeters, leaving the young leaves to 

 push out unprotected, spindling, and weak, unable to push their way 

 through soil. The roots are underdeveloped but show no deformity. 

 It has been noted throughout these experiments that the greater the 

 retardation of germination in any injured seed lot, the greater the pro- 

 portion of weak, spindling plants produced. Whether the effect of the 

 formaldehyde on the sheath is to stop growth by stopping cell division 

 or by inhibiting the growth of the cells after they have divided was 

 not determined. 



Anyone observing the seeds of the injured dry lots, the uninjured damp 

 ones, and the controls, germinating in blotters where invasion by Rhizopus 



