VIEW ARTICLE

Physiology and Biochemistry

Effect of Temperature on Symptoms of Tobacco Mosaic Virus and Movement of Photosynthate in Nicotiana glutinosa. Katie Helms, Division of Plant Industry, Commonwealth Scientific and Industrial Research Organization, Canberra City, A.C.T. 2601, Australia; I. F. Wardlaw, Division of Plant Industry, Commonwealth Scientific and Industrial Research Organization, Canberra City, A.C.T. 2601, Australia. Phytopathology 67:344-350. Accepted for publication 27 September 1976. Copyright © 1977 The American Phytopathological Society, 3340 Pilot Knob Road, St. Paul, MN 55121. All rights reserved.. DOI: 10.1094/Phyto-67-344.

When single leaves of either entire or partially defoliated plants of Nicotiana glutinosa, were inoculated by rubbing or by jet-injection with tobacco mosaic virus (TMV), systemic symptoms developed at day/night temperatures of 33/28, 30/25, 27/22, 24/19, and 21/16 C. With both methods of inoculation, systemic symptoms developed earlier in plants kept at the higher temperatures than in those kept at the lower temperatures. When inoculation was by rubbing, systemic symptoms also developed in a greater percentage of plants kept at the higher temperatures than at the lower ones. Jet-injection and also partial defoliation promoted development of systemic symptoms at the lower temperatures. In partially defoliated plants, net photosynthesis decreased with increase in temperature from about 22 C to 40 C. Moreover, accumulation of dry matter per unit leaf area (storage) decreased with increase in temperature from 24 C to 36 C. As a consequence, translocation from the leaf (the difference between net photosynthesis and storage) did not change significantly with increase in temperature. Thus, there was no evidence to support the generally accepted view that systemic symptoms develop only at temperatures above 30 C and there was no evidence that a temperature of 30 C is critical in translocation.