IMPORTANCE OF POTASSIUM. 



29 



Secondary potassium phosphate possibly forms loose combinations 

 with proteins more easily than does sodium phosphate, since an increase 

 of potassium phosphate is generally accompanied by an increase of 

 proteins, as in the seeds. Pollen grains also seem to be rich in this 

 salt; at least Raman n found that of the ash in the pine pollen 50.74 

 per cent was potash and 80.08 per cent phosphoric acid. Seeds 

 always contain much more potassium phosphate than sodium phos- 

 phate, while on the other hand the proportion of soda to potash in 

 form of other salts than phosphates is often found to be larger in the 

 leaves and roots. a 



The following table shows the composition of seeds of Graminea? and 

 Leguminosa?, the latter containing, as is known, relatively more protein 

 than the former: 



Analysis of the seeds of Graminese and Leguminosse. a 



Product analyzed. 



Number 

 of 



analyses. 



Graminese: 

 Wheat . 

 Rye.... 

 Barley . 

 Maize. . 

 oats ... 

 Millet . 



98 

 20 

 50 



9 

 23 



3 



Average 



Leguminosse: 



Vetch 



Pea 



Lupin 



Soybean 



Field bean ( Vieia) 



Garden bean | Phaseolus) 



Average 



3 



29 



3 



1 



15 

 13 



Total ash 

 Average. 



Per cent. 



1.97 

 2. 09 

 2.60 

 1.51 

 3.14 

 3.43 



Average in 100 

 parts of ash. 



Soda. 



Per cent. 



2.25 

 1.70 

 2. 53 

 1.83 

 2.34 

 1.30 



2. 457 



L.99 



3.10 

 2. 73 

 3.95 

 2. 83 

 3.57 



7.80 

 0.96 

 0.37 

 1.08 

 1.34 

 1.49 



3.23 



2.17 



Potash. 



/'< r cent. 

 31.10 

 31.47 

 20. 15 

 27. 93 

 16. 32 

 11.39 



Protein. 



I'< /■ cent. 

 11.0 

 10.3 

 10.1 

 10. 

 9.8 



23. 07 



10.2 



30. 14 

 41. 79 

 29. S4 

 47.00 

 42. 49 

 44.01 



39. 21 



27.9 

 22. 7 

 35.3 

 33.2 

 24.8 

 24.3 



29.0 



« These figures were taken from E. Wolff's Asehen Analysen, Vol. 1. 



Calculating from the above data the amount of soda and potash for 

 1,000 parts of dry organic matter, the seeds of Graminea? contain 0.48 

 part soda and 5.67 parts potash, while those of Leguminosse contain 

 0.70 part soda and 12.66 parts potash. It is seen, therefore, that on 

 an average there is more potash in seeds which are richer in protein, but 

 the ratios in the various cases do not show a close relation. For the 

 Graminea? the average proportion of potash to protein would be as 1 



" In some cases the amount of soda found in the leaves exceeds even that of potash. 

 Wolff's tables give for the leaf of Daucus carota a total ash content of 13.53 per cent 

 for the dry matter, and for 100 parts of this ash L9.83 parts soda, hut only 11.26 parts 

 of potash. The occasionally rather large soda content in the leaves is due to the 

 current of transpiration, containing sodium salts among other things. 



