INHIBITION OF SEED-GERMINATION AND SEEDLING GROWTH BY CLEOME DROSERIFOLIA AND ALLELOPATHIC EFFECT ON RHIZOSPHERE FUNGI IN EGYPT

The effect of Cleome droserifolia shoot extract on its seed germinatio n and seedling growth was examined. The possible allelopathic effects on the soil mycoflora were also assessed. The plant water extract caus ed negative effects on the seed germination and seedling growth, i.e. Cleome droserifolia is autotoxic. The soil mycoflora exhibited suppres sed mycelial relative growth rate, spore germination, sporulation and reduced length of the germ tube in response to increased extract conce ntrations. Due to the allelopathic effects, the number of fungal speci es and the total count in the rhizosphere was less than that in the no n-rhizosphere soil. The species with relatively high colony counts in both rhizosphere and non-rhizosphere soils, such as Aspergillus niger, were less inhibited by the plant water extract. The two species Penic illium chrysogenum and Penicillium funiculosum were the test fungi mos t sensitive to the allelopathic effects of Cleome droserifolia. Rhizop us stolonifer was the only isolated species found to be resistant to t he allelopathic effects.