Growth regulating activity of metabolites of terrestrial plants and marine organisms – water, alcohol and lipidic extracts, polysaccharides, diterpene, triterpene and steroidal glycosides, alkaloids, pigments, decumbenones and B,B'-triketones were studied. It was defined that some of the studied substances are capable to stimulate, inhibit or be inactive in relation to the main root of seedlings of agricultural plants. Extract and triterpene glycoside of hederagenin cauloside C, isolated from Caulophyllum robustum Maxim., and monosulfated cucumariosides group A_2, isolated from of the Far Eastern edible holothurian Cucumaria japonica, inhibit the growth of seedlings the main root of Cucumis sativus. Among of decumbenones A (1), B (2) and C (3), isolated from the marine-derived strain of the fungus Aspergillus sulphureus, decumbenone A (1) stimulates the growth of seedling roots of Triticum aestivum and Zea mays. Among of alkaloids 1-9, isolated from the marine fungus Aspergillus fumigatus, of alkaloid 3 stimulated the growth of seedling roots of ?rysa sativa and Fagopyrum esculentum. The water extracts of F. esculentum (of the red-stem population) at a concentration of 10^-8 g/ml stimulated productivity of one plant F. esculentum by 67% and content of rutin in F. esculentum plants by 20% more than in the control.