CAUSES OF REDUCED PATHOGEN TOLERANCE IN PELARGONIUM AFTER APPLICATION OF SILVER THIOSULFATE

A silver thiosulfate (STS)-mediated increase in pathogen susceptibility was investigated using shoot cuttings from stock plants of pelargonium (Pelargonium hortorum Bailey cv. Ringo Scarlet) with and without STS treatment. Callusing and rooting were reduced in shoot cuttings from STS-treated plants. The pathogen-tolerant tissue (no STS) was shown to produce enhanced levels of phenolic esters and glycosides during wound healing. Reactivity to the histochemical stain phloroglucinol-HCL was also enhanced during wound healing in cuttings from plants that had not received a silver treatment.