Here, we examine the effect of
saccharin on the induction of systemic resistance in broad bean (Vicia faba) to the rust fungus Uromyces viciae-fabae.
Saccharin was applied to beans at the three-leaf stage, either as a soil drench or by painting the
solution on to first leaves. Plants were then challenge inoculated with the rust 1, 6, 10 and 14 d following
saccharin treatment, after which they were harvested, assessed for the intensity of rust
infection and plant growth measurements conducted. Foliar application of
saccharin did not induce systemic protection to rust
infection until 14 d after application and was less effective than
saccharin applied as a soil drench. When
saccharin was applied as a drench, systemic protection was not observed until 6 d after application, but was still apparent in plants 14 d after application of the drench. Irrespective of the method of application,
saccharin had no significant effect on fresh and dry weights or leaf area of the plants.
Saccharin applied as a drench did, however, reduce the number of leaflets produced.