Abstract: Plant roots could secrete exudates which contain root-specific metabolites. Those metabolites have critical effect on the growth of the plant itself. Germination and early seedling growth bioassays were used to assess the autotoxicity potential of root exudates from Fritillaria pallidiflora Schvek in the present paper. The results indicated that the germination percentage, radical and hypocotyl length were inhibited by 1,3,5-triallyl-1,3,5-triazine-2,4,6(1H,3H,5H)-trione, phenols, and their mixtures, which are the main constituents of root exudates. The root exudates collected by the continuous cyclic device had effect on seed germination, and the autotoxicity were increased with higher concentration in a certain range and decreased beyond the range. The root exudates autotoxicity on its early seedling growth increased with higher concentration, however, they promoted the hypocotyl length of F.pallidiflora at lower concentration.

Key words: Fritillaria pallidiflora Schvek, root exudates, seed germination, autotoxicity