IQIS ] ROSE— DELAYED GERMINATION 43 1 



are more certain to be productive than those that for any reason 

 are weak from the beginning. 



Before this machine can become commercially practicable, 

 experiments must be conducted to determine: (i) the possibility 

 of substituting something else for needle points; (2) the proper 

 distance these points should be from each other to give the best 

 results for different sized seeds; (3) the pressure necessary to give 

 the best germination for different kinds of seeds; for certain 

 legumes a pressure of two to three pounds is necessary, for lettuce 

 one pound or even less; (4) the effect of storage on the germination 

 of treated seeds; (5) the germination of treated seeds in soil. To 

 be effective in overcoming hard-coatedness, the needle point need 

 only pass through the palisade layer and not entirely through the 

 coat. Even with this slight deformation it is possible that bacteria 

 and fungi can gain an entrance. That destruction by bacteria 

 and fungi actually does take place was shown by Jarzymowski (17) 

 for seeds of Ulex europaca, lupines, and other large-seeded legumes 

 which had been treated with the Wissinger machine. Red clover 

 and Lotus comic ulatus were the only ones whose germination in 

 soil after treatment was not seriously reduced. 



As to the germination in soil of seeds treated by the blowing 

 method here described, there are not at present enough data on 

 hand to justify the drawing of definite conclusions. Preliminary 

 experiments seem to indicate for alfalfa seed, where the percent- 

 age of hard seed is high, that germination in soil is definitely better 

 after treatment than before. Further investigation, of course, is 

 necessary before this can be confirmed. In conclusion it may be 

 stated that there was no serious crushing or cracking of seeds or 

 seed coats by this machine. 



The need of after-ripening 



This is a condition which occurs, to mention only a few cases, 

 in seeds of Crataegus, various conifers, Fraxinus, potato tubers, 

 and lily-of-the-valley bulbs. For a discussion of the general situ- 

 ation and a resume of the literature the reader is referred to the 

 paper by Eckerson (10) dealing with after-ripening in the seeds 

 of Crataegus. The work to be discussed here had to do with the 



