摘要：Sulfur content in orange leaves was determined by microbiological assay method using Escherichia coli B (H), and concentration of sulfur oxides in air was discussed. Sulfur content in each orange leaf of one grown-up tree gave large standard deviation (11-29%), and no significant correlation was observed between this sulfur content and concentration of sulfur oxides in air. On the other hand, some significant correlation was observed between sulfur content in orange leaves of young trees grown in a pot (pot-test) and concentration of sulfur oxides in air. These result suggested that the sulfur content in orange leaves obtained by this pot-test method was useful as an index of concentration of sulfur oxides in air.
