MISCELLANEOUS 419 



tion, but this treatment was ineffective compared with low-temperature 

 stratification or ilkmiination of the seeds while under water. Treatment 

 with growth substances had no beneficial effect on the germination of dor- 

 mant seeds of a variety of domestic apple and a species of crabapple. Low- 

 temperature after-ripened seeds of Cornus and Pyrus were thro^^•n back 

 into dormancy by treatment with growth substances. Growth substances 

 did not force the growth of the naturally dormant epicotyls of seeds of 

 Paeonia, Viburnum, or lily., 



Youden ^^- p--^^ describes a set of experiments in which he treated wheat 

 and soybean seeds with growth substances. ''WTieat and soybean seeds 

 were treated in the dry state with indoleacetic acid, naphthaleneacetic 

 acid, and indolebutyric acid, talc, and Rootone (commercial preparation) 

 and gro\vn in sand and soil in the greenhouse and in the field. The con- 

 centration of the organic compounds in the talc preparations, as well as 

 'the proportion of powder to seeds, was adjusted to cover the range 0.5 to 

 240 parts per million of active substance by weight of the seeds. In a 

 series of ten experiments observations were made of the germination, 

 seedling height, wet weight of tops, yield of grain, and root systems, and 

 no significant case was found in which the germination and growth of the 

 treated lots exceeded the controls. On the contrary the aggregate of evi- 

 dence points to slightly lower values for the treated lots, and indicates 

 that these are the result of the presence of the talc. Nineteen contrasts of 

 talc-treated seeds with controls gave fifteen cases in w^hich the controls 

 were superior and one tie. On the average, the excess weight of the con- 

 trol plants was about 5 per cent." 



An experiment was conducted to test the report that treatment of grass 

 seeds with plant hormones stimulated the growth of lawns. Fig. 168 shows 

 that there were no beneficial effects on any of the 14 plots tested. 



In 1939, Better Homes and Gardens published an article announcing the 

 remarkable stimulative effect of vitamin Bi on green plants. It was said to 

 produce veritable giants out of garden and house plants and to make trans- 

 planting entirely safe when plants were m full bloom. The article would 

 lead one to think that the greatest discovery of modern horticulture had 

 broken upon an unexpecting world. 



Investigators ^^' ^'^^ at this Institute as well as most of many investigators 

 elsewhere who have worked upon the problem have found that vitamin Bi 

 has no such remarkable effects upon growth of higher green plants — 

 indeed that it has very minor, if any, effects. The B group of vitamins is 

 an important accessory factor in the growth of various non-chlorophyllous 

 plants, such as yeasts and fungi. If vitamin Bi is important for the growth 

 of higher green plants it is likely that these plants synthesize an adequate 

 supply to meet their needs. 



Zimmerman ^°^' p-^'* says: "The preponderance of evidence from scien- 

 tists is opposed to the use of vitamin Bi for practical purposes. My own 

 convictions, based on our experience at the Boyce Thompson Institute and 



