14 
I. NAGAI : 
4. Pi ole of Oxygen in the Development of the Chbomogenic 
Substance and Anthocyanin. 
It is already known that the formation of antliocyanin is suppressed when 
the normal oxygen relation is artificially checked in the living plant. 1 
The writer observed that the hypocotyls of the seedling of the buckwheat 
remained white as long as they were kept in the dark, but when exposed to 
the day light, a deep red colour developed. If they were kept in the glass 
chamber in which the air was replaced by hydrogen gas, they did not form 
the pigment even wdien exposed to the day light. The chromogenic sub¬ 
stance could be detected from the colourless samples. The alcoholic extract 
gave a distinct red colour by reduction by means of hydrochloric acid and 
magnesium powder. 2 
The young seedlings of certain varieties of soy bean form a deep purple 
anthocyanin pigment together with chlorophyll in the elongated hypocotyls a 
few days after germination, if they are exposed to strong sun light. If, how¬ 
ever, the normal supply of air is checked, the pigment does not develop as 
in the case with the buckwheat. The following experiment shows clearly the 
above relation. The young seedlings of a variety of yellow cotyledon which 
were devoid of both pigments, were placed under the following conditions : 
Lot A. A small, tightly fitted glass chamber in which the air was 
replaced by hydrogen gas which was generated by Kipp’s apparatus and 
washed by the solution of potassium permanganate once. The chamber was 
dipped in water. 
Lot B. Same as A, but the chamber was kept in the air. 
Lot C. The chamber was simply closed up. 
Lot D. The chamber opened, as control. 
All the chambers were kept in a glass case which was placed near the 
1. Emeey, VT.,.; Sur les variations «le F eau dans les perianthes. Bull. Soc. Bot. France. 
3G : 322, 1889. Katic, D. L., Beitrag zur Kenntnis der Bildung des roten Farbstoffs (Anthocyan) 
in vegetativen Organen der Phanerogamen. Inaug. Dissert., Halle. 1905. Cited in AVheldale, 
M., Antliocyanin Pigments of Plants. 1916. 
2. See also Miege. E., Becherclies sur les principales espèces de Fagopyrum. Thèse de 
Doctorat de 1, Univ. Paris. 1910. Cited in Combes, B., Recherches biochemiques experimentales 
sur le rôle jihysiologique des glucosides chez les végétaux. Rev. General, d. Bot. 30: 89, 1918. 
