STUDIES ON THE METABOLISM OF LEAVES WITH LOCALIZED VIRUS INFECTIONS: I. OXYGEN UPTAKE

Abstract

Infection of Nicotiana glutinosa with tobacco mosaic virus, of Dianthus barbatus with a carnation virus, of Gomphrena globosa with potato virus X, and of N. tabacum with two strains of turnip mosaic virus produced local lesions and significantly increased O₂ uptake to an extent dependent upon the stage of infection. Increased respiration in N. glutinosa, as measured by O₂ uptake, was detected 7–10 hours before lesions appeared. When infected plants were maintained at 32 °C, the rise in respiration occurred 8–15 hours before the appearance of lesions, indicating an increase or prolongation of virus multiplication. Local lesion infection of other hosts, though differing in detail, had essentially the same effect. Non-virus injury, including artificially produced necrotic local lesions, did not induce a similar increase in respiration. When necrotic areas were excised from infected disks the remaining portions still respired at a greater rate than healthy controls. Increased respiration appeared to be correlated with virus activity other than the necrotic process.