Table II.

Effect of MeSA on SA concentration and TMV-lesion size in wild-type and NahG tobacco plants

PlantSALesion Diameter
d 0d 6
ng g−1 fresh wtmm
Wild type34  ± 16546  ± 6830.852  ± 0.04
NahG45  ± 484  ± 171.785  ± 0.08

Tobacco plants were enclosed in gas-tight glass chambers to which 250 μg L−1 MeSA was supplied daily. After 6 d of incubation the plants were sampled and analyzed for SA content. Each value is the mean ± se of three replicates. Plants were then inoculated with TMV, and the diameter of the TMV-induced lesions was measured 72 h postinoculation. Data represent the mean diameter ± se of at least 30 lesions per plant. The experiment was repeated with similar results. The diameters of TMV lesions in untreated wild-type and NahG plants were 1.328 ± 0.09 and 1.800 ± 0.11 mm, respectively.