The Anther Smut of Sea Campion

The sympton of dwarfing in the sea campion, Silene vulgaris (Moench) Garcke sub sp. maritima(With.) A. & D. Löve infected with the anther smut fungus Ustilago violacea (Pers.) Fuckel, a systemic, perennial parasite, has been investigated. Extracts of both healthy and diseased plants contain IAA and GA3, but diseased plants contain less gibberellins than healthy plants. Neither IAA nor gibberellins were detected in significant quantities in the medium when U. violacea was grown in pure culture, but IAN was present. IAN was also found m extracts of diseased plants and it is tentatively suggested that it is formed by the fungus and may accumulate in the host owing to the inability of the plant to convert IAN to IAA The exogenous application of IAN to healthy plants does not produce any disease symptoms. The dwarfing symptom of the diseased plant may be due to the lower levels of gibberellins which it contains compared with healthy plants since the exogenous application of GA3, restores the diseased plant to normal growth