Rapid Diagnosis of Viral and Fungal Diseases in Plants by Pyrolysis and Gas-Liquid Chromatography

Abstract

WE have approached the diagnosis of plant diseases using a technique similar to that used by Reiner and Ewing¹ in recognizing strains of Escherichia coli. This involved analysing thin transverse sections of leaf tissue from diseased and healthy (control) plants by pyrolysis and gas-liquid chromatography, and comparing the chromatograms. A Pye ‘Series 104’ Model 24 gas-chromatograph was used, with dual flame ionization detector, pyrolysis assembly and ‘Pyrex’ glass columns 1.5 m long by 4 mm diameter packed with ‘Carbowax 20M’ plus phosphoric acid (solvent, dichloromethane). Comparative samples were taken from leaves, inserted in the pyrolysing element and pyrolysed at 800° C. Analyses took place in a stream of nitrogen (45 ml./min), under a programmed rise in temperature of 8° C/min from 40° to 140° C commencing at the moment of pyrolysis. At maximum temperature the analysing column was cleared and ready for the next sample in less than an hour. The instrument was used at attenuation level ×500.