Banafsheh Heidari Koholi - Master of Science, Payame Noor University, Najafabad, Iran
Mohammad Hassan Assareh - Scientific board, Seed and Plant Certification and Registration Institute, Karaj, Iran
Shoukufeh Enteshari - Scientific board, Payame Noor University, Najafabad, Iran
Anahita Shariat - Scientific board, Research Institute of Forests and Rangelands, Tehran, Iran

The use of allelochemicals as natural herbicides is a new approach to reduce the adverse effects of chemical herbicides on the environment and prevent weed resistance to herbicides. In this study, the allelopathic effect of Eucalyptus camaldolensis leaves and roots on Festuca ovina was tested in greenhouse conditions in ۲۰۰۸ at the Research Institute of Forests and Rangelands. This study was conducted as a completely random design with three repetitions and comparing the means with Duncan's test at the level of ۰.۰۵. The treatments used in the greenhouse stage were: control, dried leaf powder (۵, ۱۰, ۱۵ grams), fresh leaf powder (۵, ۱۰, ۲۰ grams), ethanolic extract of leaves (۳, ۶, ۱۲ grams per liter), aqueous extract of dry leaves (۵, ۱۰, ۱۵%), aqueous extract of fresh leaves (۱۰ and ۲۰%) and root secretions. In some pots, ethanolic extract of dry leaves (۳, ۶, ۱۲ g/liter) was sprayed on the leaves. The parameters measured in this study include fresh and dry weight of biomass, stem and root, relative water content (RWC), leaf water content per unit of leaf area (LWCA), specific leaf area (SLA), and leaf area (LA). The results showed that in all the measured traits, the most inhibitory effect was related to the ethanolic extract, the aqueous extracts of fresh leaves and dry leaves also had an inhibitory effect, and the measured parameters also showed a decrease. The used fresh and dry leaf powders acted as a covering layer and prevented soil moisture from escaping. The effect of root secretions was also investigated in the pots containing one-year-old eucalyptus seedlings, and in this case, the root secretions completely prevented the seeds from germinating.

Allelopathy, Eucalyptus camaldolensis, Festuca avina, growth parameters, root secretions