Sulfur Metabolism in Higher Plants

1. The Conversion of Sulfate into Organic Sulfur in Excised Leaves

Abstract

The contents of organic sulfur in various seedlings did not increase but rather decreased during the cultivation-period within 8 to 12 days. In mung bean seedling, the synthesis of organic sulfur from sulfate took place only in the leaves. Organic sulfur in the roots and stems may be transported from the cotyledons. Even in the excised leaves, the rapid conversion of sulfate into organic form took place both in air and reduced pressure. The organic sulfur compound synthesized during the incubation for the short period was cystine or cysteine and methionine was detected only after a long time. It may be possible that this system is employed in studies on the pathway of the conversion of sulfate into organic form.