Abstract

A number of laboratory and field experiments have performed with aqueous extracts from fresh leaves, fallen leaves and roots of Pinus rigida in order to investigae the effetct of the pine tree. The results obtained found its inhibitive effect on the germination and growth of tested species. Though relative germination ratio of the species was somewhat lower than the control plot, severe inhibition was observed in relative dry weight ration, These results were more obvious in aqueous extracts than in the case of leachates and similar results were also confirmed by field bioassays on the forest soil of P. rigida. Therefore, to find out the inhibitory sybstancesm 14 different kinds of KDICical substances were isolatd from the leaved of the tree by chromato-graphy and nist if them were confirmed to be phenoic compounds, The growth of lettuce was inhibition was observed in the concentration of less than 5X10-3M soluton. Phenolic compounds are assumed the substance related to the allelopathic effect of P. rigida.

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