The Allelopathic Effects of Fresh and Dry Eucalyptus sp Leaves and Their Extracts on Germination and Some Vegetative Characters of Some Ornamental Plants.

Abstract

The present study is conducted to study the effect of fresh or dry leaves of Eucalyptus sp and their extracts on seed germination and some vegetative characters of four ornamental plants namely; Calendula officinalis, Tagete patula, Mathiola incana and Asteriscus graveolens. The results show that the treatment with ethanolic extract, oil, or some other compounds extracted from Eucalyptus leaves such as terpenes, alkaloids and phenols at different concentrations cause significant reduction in germination percentage of Calendula officinalis, Tagete patula and Mathiola incana. Treatment with oil and the other three compounds cause significant reduction in plumule and radical length. Also, the results show that the treatment with dry or fresh leaves cause significant decrease in plant height, which increases as the concentration of treatment increase, especially at the dry leaves treatment. However, plant height of Calendula increase at the 2g dry leaves/kg treatment. In addition, the treatment with fresh leaves has an obvious effect on all tested plants. Also, the number of branches is reduced in both kinds of treatments in Calendula and Tagete plants. The interaction between the different concentrations of all treatments and kind of plants reveals that the higher concentrations of the different treatments , the more different results are.