Buckwheat Seedlings May Inhibit Other Plant Growth by Allelopathic Substances

Donor-receiver bioassay was designed to eliminate the effects of the competitive interference for resources from allelopathic effects. Seeds of cress (Lepidium sativum), lettuce (Lactuca sativa), timothy (Phleum pratense) or ryegrass (Lolium multiflorum) were incubated with 4-day-old buckwheat (Fagopyrum esculentum) seedlings for 3 days in Petri dishes under controlled laboratory condition. The growth of cress, lettuce, timothy and ryegrass seedlings was inhibited by the presence of buckwheat seedlings, and increasing the number of buckwheat seedlings increased the growth inhibition. One inhibiting substance was found in the culture solution in which buckwheat seedlings were hydroponically grown for 10 days. These results suggest that buckwheat seedlings may inhibit the neighboring plant growth due to exudation of allelopathic substance into the neighboring environment. Thus, the inhibitory effect of buckwheat was probably caused by allelopathic chemical reactions.