Role of oxalic acid in the Sclerotinia wilt of sunflower.

摘要: Leaves of greenhouse-grown sunflower plants infected with Sclerotinia sclerotiorum frequently exhibit wilting and inter-veinal necrosis 3 to S days after inoculation. A wilt-inducing substance was found in water extracts hypocotyl, lesions. Chemical tests, thin-layer chromatography gas-liquid demonstrated that wilt-active aliquots purified hypocotyl contained oxalic acid. Wilted leaves from over 15 times more acid than healthy plants. Healthy fed through the showed foliar symptoms identical those associated fungal infections, concentrations treated were equivalent The pH xylem sap taken 2 cm above lesions one unit lower Oxalic detectable moves systemically where it apparently accumulates a “critical” level elicits wilt syndrome. varietal screening technique using whole leaf cell suspensions developed which indicated cultivars resistant tolerant during their flowering period.