Abstract: In order to understand the synergistic interaction between woody plant and herbs, the growth indicators of rapes and Orychophragmus violaceus plants, such as germination rate, length of hypocotyls, root length, hypocotyl coarsenes, fresh weight, dry weight, were observed by processing the deciduous extract of poplars and North American Begonia. The results showed that the deciduous extract of poplars decreased seeds germination rate, length of hypocotyls, root length, fresh weight, dry weight of the rapes by 30.0%, 58.6%, 78.4%, 44.9%, 52.7%, and reduced the germination rate, root length, fresh weight, dry weight of Orychophragmus violaceus by 36.7%, 69.9%, 77.1%, and 62.7%. The water extract of the North American Begonia deciduous leaves reduced rape seeds germination, the root length by 21.1% and 54.0%. Compared with the control of rape seed hypocotyl coarseness increased by 21.2%, the germination rate, root length, fresh weight, and dry weight of the Orychophragmus violaceus decreased by 24.5%, 57.6%, 39.9%, and 53.7%, and the length of the embryonic axis of Orychophragmus violaceus was significantly increased by 87.3%. In summary, the extract of the poplar and the North American Begonia had inhibitory effects on the seed germination and plant growth of the rapes and Orychophragmus violaceus. The effects of the poplar deciduous leaves on the germination and seedling growth of rape seeds and Orychophragmus violaceus seeds were stronger than that of the North American Begonia.

Key words: allelopathy, woody plants, cruciferous, germination, growth