- 128 - 



1 



H. B. HUTCHINSON and N. H. J. MILLER. Direct Assimilation 

 of Ammonium Salts by Plants. [Rothamsted Experiment 

 Station]. (The Journal of Agricultural Science, Vol. Ill, Part 2, 

 October 1909). 



See also : Contributions from the Laboratory *f the Rothamsted Ex- 

 perimental Station. Cambridge, 1909, p. 171. 



Whilst non-leguminous crops, whether able to assimilate ammonia 

 or not, undoubtedly take up, under normal conditions, most of their 

 nitrogen in the form of nitrates, we have no knowledge of the 

 form of nitrogen appropriated by leguminous plants from their root 

 nodules. The authors before describing in this article the experi- 

 ments on assimilation of ammonium salts by plants, take into con- 

 sideration recent experiments in which nitrification has been taken 

 into account, in order to show in some detail what has been al- 

 ready done: 



A. Griffiths: Direct absorption of ammoniacal salts by plants. 

 Chem. News 1891. 



A. Miintz: Sur le role de 1'ammoniaque dans la nutrition des 

 ve"getaux supdrieurs. Comptes-Rend. 1889. 



M. Gerlach and P. Vogel: Ammoniakstickstoff als Pflanzennahr- 

 stoff. CentbL Bakt. Par., 1905. 



If some plants (Sorghum) are not adapted for an ammoniacal 

 nourishment, others (maize) prefer it, others again (rice) grow better 

 when nourished both with nitrates and with ammonia salts. 



Sterilisation of seeds, and all other precautions were taken to 

 avoid the possibility of nitrification in the reported experiments, 

 and the results show that ammonium sulphate is directly assimi- 

 ated by wheat and peas and that in the case of peas there was 

 no difference between the plants supplied with ammonium salt and 

 those which had sodium nitrate. The wheat plants however showed 

 a decided preference for nitrogen in the form of nitrate. 



In each case in which nitrogen was applied as ammonium salts 

 the dry matter of the plants contained higher percentages of nitrogen 

 than when sodium nitrate was employed. An explanation of the 

 high nitrogen percentages seems to be afforded by Suzuki's results 

 (Bull. Coll. Agric., Tokyo, 1894-7, 2, 409-457) which showed that 

 ammonium salts are rapidly converted by the plants into aspara- 

 gine and so give rise to conditions favourable to renewed absorption 

 whilst nitrates tend to accumulate and thus check further diffusion 

 from outside. 



