ABSTRACT. Allelopathy determines the dynamics of germination, development and
growth of plant species in the environment. Therefore, in this study, the allelopathic effect
of an aqueous extract isolated from walnut (Juglans regia L.) leaves (concentrated extract,
1:2, 1:4 and 1:8) on the germination percentage, mean germination value and germination
rate of wheat (Triticum aestivum L.) and peas was monitored (Pisum sativum L.). Both
tested species were sensitive to juglone, but the percentage of germination was significantly
lower in wheat (by 80%) compared to peas, so it can be said that this species is more
sensitive. The length of roots and shoots of both tested species decreased in proportion to
the increase in the concentration of the extract. Monitoring of this biological phenomenon
could help to understand the changes in the environment caused by allelochemicals.
