Extracts from the leaves of knotweeds (Reynoutria spp.) have a stimulating effect on the germination and initial growth of wheat grains.

Knotweed (Reynoutria sp.) plants are known in the world mainly as invasive plants. However, it is known that their rhizomes or leaves contain secondary metabolites with biological activity. Our goal was to determine which of the three knotweed plants (Reynoutria japonica, Reynoutria × bohemica, and Reynoutria sachalinensis) is most suitable for seed growth stimulation. We tested alcoholic extracts of all three knotweed species by seed priming method on wheat germination and seedling characteristics, when 12 measured characteristics were monitored. Extracts from all three species of Reynoutria sp. generally showed an improvement in wheat germination and growth compared to the control. R. × bohemica appears to be the best source for stimulating wheat growth, as seedling vigor indexes I and II, R/S dry weight, shoot and seedling lengths, root, shoot, and seedling dry weights were significantly different (ANOVA, Duncan's test, α < 0.05). The plants Reynoutria spp. seem to be possible sources for the protection and stimulation of agriculture crops.