NOTES AND COMMENT 



Prof. W. F. Gericke, of the University of California — at present work- 

 ing at the Laboratory of Plant Physiology of the Johns Hopkins Uni- 

 versity on the salt nutrition project of the Division of Biology of the 

 National Research Council — presented what may be some rather start- 

 ling results at the Baltimore meeting of the Physiological Section of 

 the Botanical Society of America, under the title, A preliminary test 

 of the influence of temperature upon the effect of the physiological 

 balance of the nutrient solution as related to germination in wheat. 

 In experimentation on the relation of germination in wheat to salts, 

 salt proportions and temperature, following out a rather elaborate 

 scheme, it appears that the salts and salt proportions of the medium 

 that are best for germination with one maintained temperature are not 

 at all the same as those that are best with another maintained tempera- 

 ture. In other words, the optimum nutrient solution for wheat germi- 

 nation is different for different temperatures, and a statement of. the 

 temperature employed must always accompany any statement about 

 physiological balance in the nutrient medium. Conversely, the opti- 

 mum temperature for wheat germination cannot be stated without an 

 accompanying statement regarding the concentration, salts and salt 

 proportions of the nutrient solution referred to. So far as this work 

 has gone, it appears that the percentage of germination and the rapidity 

 of the early development of the wheat seedling depend upon the follow- 

 ing five conditions, at least: (1) the seed used (internal conditions), 

 (2) the salts used in the medium, (3) the salt proportions in the medium, 

 (4) the total concentration (osmotic value) of the medium, and (5) the 

 temperature. Of course it is to be expected that varying temperatures 

 may exert very different influences from those exerted by any main- 

 tained temperatures (only maintained temperatures have been studied), 

 and also that the oxygen and carbon-dioxide relations will not be with- 

 out influence on germination (these have not been quantitatively 

 studied) . 



These results emphasize once more how futile physiological experi- 

 mentation is unless it is carried out with all the influential conditions 

 either controlled or quantitatively defined. It is the business of plant 



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