VIEW ARTICLE

Physiology and Biochemistry

Role of Ethylene in the Response of Tomato Plants Susceptible and Resistant to Meloidogyne incognita. D. B. Akitt, Graduate research assistant, Biology Department, Brock University, St. Catharines, Ontario, Canada L2S 3A1; A. W. Bown(2), and J. W. Potter(3). (2)Associate professor, Biology Department, Brock University, St. Catharines, Ontario, Canada L2S 3A1; (3)Research Scientist, Agriculture Canada, Research Station, Vineland Station, Ontario, Canada L0R 2E0. Phytopathology 70:94-97. Accepted for publication 30 July 1979. Copyright 1980 The American Phytopathological Society. DOI: 10.1094/Phyto-70-94.

Ethylene concentrations were measured in gases from roots of tomato (Lycopersicon esculentum) plants of cultivars Vendor and Anahu which are susceptible (S) and resistant (R), respectively, to Meloidogyne incognita. No significant difference was found in root ethylene concentrations between nematode-treated and control R plants during a 30-day postinoculation period. Postinoculation ethylene concentrations in roots of infected S plants decreased significantly relative to those of the uninfected controls. Decreasing ethylene concentrations in infected S plants correlated inversely with root weight which increased significantly over the same period due to gall formation. Thus, galled roots contained less ethylene per gram than did healthy roots. These data do not support the hypothesis that increased ethylene production accompanies gall formation. Ethane concentrations varied directly with ethylene concentrations, but were invariably greater. These results are discussed with reference to recent literature on possible relationships between ethane and ethylene biosynthesis.