All experiments have been conducted at Kagawa University,
Japan since October 2009. A germination test was conducted on two
species, cress (Lepidium sativum L.) and barnyard grass (Echinochloa
crus-galli (L). Beauv.), because cress is highly sensitive to allelopathic
assays (Xuan et al., 2005) while barnyard grass is one of
the worst weeds in the world and has developed high resistance
to herbicides (Valverde et al., 2000). Seeds of cress were bought
from Takii (Kyoto, Japan).