OBSERVATIONS ON THE BEHAVIOUR OF RESTING SPORES OF PLASMODIOPHORA BRASSICAE IN THE PRESENCE OF CRUCIFEROUS AND NON-CRUCIFEROUS PLANT ROOTS

Plant spp. tested were: Brassica oleracea var. sabauda, var. gongylodes, var. capitata f. rubra and f. capitata, var. gemmifera, var. botrytis, B. napus var. napobrassica, B. pekinensis, B. juncea and Lycopersicon esculentum, Cucumis sativus, Allium cepa, Allium porrum.

After 5 days the seedlings were removed and the residual spores investigated using the fluorescence microscope method (Takahashi and Yamaguchi 1988). The percentage of viable spores was determined.
Non-viable spores were considered to be germinated or dead.

The germination of P. brassicae resting spores was stimulated by cruciferous and non-cruciferous plant roots compared with the water control.
Germination rate was unrelated to the compatibility the test plant species to P. brassicae. It is concluded that the germination of resting spores of P. brassicae was encouraged by the presence of young plant roots.
The root-borne substance/s stimulating spore germination are of a non-specific character.