Manganese Deficiency in Oats

THE value of the water culture method for the study of the role of particular chemical elements in the nutrition of higher plants is generally recognized, and the more exactly the chemical constitution of the culture solution is controlled the more effectively can the study of trace elements be undertaken. By using the water culture technique of Stout and Arnon¹, I have produced the typical symptoms of grey speck disease in oats attributed to manganese deficiency only four weeks after sowing, as well as evidence that this technique will prove valuable in studying the physiological importance of other elements. The method, not previously used by workers in Great Britain, so far as I am aware, involves the use of: 1, `Pyrex' or `Hysil' glassware; 2, re-distilled water²; 3, specially purified solutions¹; and 4, the diphenylthiocarbazone colorimetric test³ for metal impurities in water and nutrient solutions.