Distribution of the Products of Photosynthesis between Powdery Mildew and Barley

Abstract

The photosynthetic assimilation of C14O2 was studied in healthy and mildew-infected barley. The parasite was separated from the host by removing the mycelium with a camel''s hair brush. The ethanol soluble metabolites of the parasite, infected host, and healthy host were extracted, separated by paper chromatography, and individually identified. From this work it appears that there was a rapid movement of label from host to parasite mainly in the form of sucrose which was then quickly metabolized into many compounds. The majority was converted into mannitol, and lesser amounts were converted into trehalose, arabitol, aspartic acid, and glutamic acid. In conidia the major C reserve was arabitol instead of mannitol, with lesser amounts of trehalose and mannitol. Photosynthetic uptake of C14O2 by the complex decreased steadily after inoculation as compared with healthy leaves. However, the ethanol-soluble metabolites of the infected host tissue differed only slightly from those of healthy host tissue. The major differences were a slight decrease in the amount of sucrose and increases in malic acid and serine.