The allelochemicals of eucalyptus maidenii essential oil and its potential as natural herbicide

This study aimed to explore the allelopathic potential of Eucalyptus maidenii on seed germination, root and shoot length, membrane integrity, malondialdehyde (MDA) and proline content of Triticum durum, Vicia faba, Phaseolus vulgaris, Sinapis arvensis, Erica vesicaria and Scorpiurus muricatus and its application as naturally occurring herbicide in the field. Allelopathic compounds were identified using chromatography mass analysis. Dose-response studies were carried under laboratory and greenhouse conditions.  Germination, emergence and seedling growth of test species were significantly inhibited in a dose-response bioassay. In a greenhouse, observation of leaf wilt symptoms was noted at 6h after treatment. Chlorophyll content was decreased with increasing of concentrations indicating that essential oil affects the photosynthetic activity. In addition, E.maidenii essential oil induces an electrolyte leakage indicating membrane damage and loss of integrity and enhanced the level of proline suggesting induction of oxidative stress. The test plants responded differently to E.maidenii essential oil exhibiting a differential species-specificity. Indeed, the weeds were affected more strongly than the crops. Developing the natural herbicide to replace the traditional agrochemicals becomes an important subject seeing that the use of synthetic agrochemicals has caused serious environment pollution due to their poor biodegradability. These results indicated that E.maidenii essential oil exhibited potential as natural herbicides and provide helpful information to develop new and potent bioactive chemicals from natural products.