ASH CONTENT IN NORMAL AND IN BLIGHTED 



SPINACH 



By Rodney H. True, Physiologist in Charge, Otis F. Black, Chemical Biologist, and 

 James W. Kelly, Laboratory Technician, Plant Physiological and Fermentation 

 Investigations, Bureau of Plant Industry. 



In view of the fact that disease conditions not infrequently profoundly 

 modify the demands of the organism for mineral constituents, a study 

 of the ash was undertaken in the hope of getting some light on the nature 

 of the abnormal conditions set up in the spinach by the disease-producing 

 agent. 



Typical normal and diseased material was selected by Mr. McClintock 

 from the fields of truck growers living near the Truck Experiment Sta- 

 tion. The plants were collected in February, 191 5, the roots and stems 

 being carefully dug out by means of a. spade. The adhering soil was 

 immediately washed off as well as could be done in the field, and the 

 plants, well wrapped up, were taken to the laboratory, where they were 

 weighed and spread out to dry. 



After they had become thoroughly air-dry, the samples were ashed in 

 an electric oven at a temperature of about 700° C. at a cherry-red color. 

 After the quantity of total ash had been ascertained, its constituents 

 were determined according to the methods of the Association of Oflficial 

 Agricultural Chemists.^ 



Table I.- 



-Ash content of healthy and diseased spinach plants 

 [Calculated as percentage of total ash] 



The results are shown in Tables I and 11. In Table I the total ash is 

 given as percentage of the total weight, air-dry, and the constituents 



WiiBY, H. W., ed. OFFICIAL and provisionai, methods op analysis, association op ofpiciai, 



AGRICULTURAL CHEMISTS, AS COMPILED BY THE COMMITTEE ON REVISION OP METHODS. U. S. Dcpt. AgT. 



Bur. Chem. Bui. 107 (rev.), 272 p.. 13 fig. 1908. Reprinted in 1912. 



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