Inhibition of seed germination and seedling growth byCleome droserifolia and allelopathic effect on rhizosphere fungi in Egypt

The effect of Cleome droserifolia shoot extract on its seed germination and seedling growth was examined. The possible allelopathic effects on the soil mycoflora were also assessed. The plant water extract caused negative effects on the seed germination and seedling growth, i.e. Cleome droserifolia is autotoxic. The soil mycoflora exhibited suppressed mycelial relative growth rate, spore germination, sporulation and reduced length of the germ tube in response to increased extract concentrations. Due to the allelopathic effects, the number of fungal species and the total count in the rhizosphere was less than that in the non-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 Penicillium chrysogenum and Penicillium funiculosum were the test fungi most sensitive to the allelopathic effects of Cleome droserifolia. Rhizopus stolonifer was the only isolated species found to be resistant to the allelopathic effects.