The determination and occurrence of a hydrojuglone glucoside in the walnut.

In the preceding paper (Daglish, 1950) it was shown that juglone existed in the walnut as the glucoside of 1:4:5-trihydroxynaphthalene and not as free anor P-hydrojuglone as previously suggested (Mylius, 1885a, b). In order to determine its role in the economy ofthe plant, the occurrence ofthe glucoside was determined during the 1948 and 1949 growing periods. The methods used, together with the results, are discussed below.