Abstract :
ABSTRACT: Allelopathic materials inside a tree can produce major changes in the survival, growth, reproduction and behavior of other organisms if they escape into the environment. These effects can be positive or negative. For these reasons, a factorial experiment in randomized complete block design (RCBD) was conducted with four replications in 2011 at the University of Maragheh, Iran, to evaluate the allelopathic effects of Cupressus arizonica on seed germination and seedling growth of Lolium perenne and Poa pratensis. Aqueous leave extracts of C. arizonica at 25, 50 and 100 gL-1 concentrations were prepared and distilled water was used as a control. The results showed that the C. arizonica extracts had an inhibitory effect on the seed germination, and the seedling growth of both studied grasses and with increasing in extract concentration the inhibition rate was increased. The effect of C. arizonica extracts on Poa pratensis was more severe than the Lolium perenne. Our results indicate that the seedling growth, especially radicle elongation, was relatively the more sensitive indicator to evaluate the effects of extracts than the seed germination.
