علی عزیزی

Endophytes are microorganisms that whole or part of their life cycle colonize inside the healthy tissues of the host plant, without causing no apparent symptoms of disease. They have many benefit for host plants, for example promoting their growth by mobilizing nutrients, producing plant growth regulators, protecting them from pathogens and etc. The choice of the plants to study of their endophytes is important. Therefore, medicinal plants which are known to be used as an alternative source of medicine, are a valuable source [1]. Lemon verbena, Lippia citriodora Kunth. from family Verbenaceae, is a shrub indigenous to South America. It is cultivated mainly due to the lemon-like aroma emitted from its leaves. Lemon verbena has a long history of folk medicinal uses in treating asthma, spasms, cold, fever, flatulence, colic, diarrhea, indigestion, insomnia and anxiety [2]. The aim of present study was to evaluate the effects of endophytes isolated from L. citriodora on the growth parameters and antioxidant property. In total, 24 fungul and 24 bacterial endophytes were isolated from different tissues of L. citriodora. Among them, bacterial (B10) and fungul (F14) isolates that were identified as Sphingomonas paucimobilis and Aspergillus sp., respectively, were selected to inoculate the plants. They were isolated from root and crown tissues, respectively. It was found that both of them significantly increased the plant growth parameters including plant height, leaf number, fresh weight and dry weight of shoot, root and leaf, compared with noninoculated control. However plant height and root weight in the S. paucimobilis inoculated plants was more than Aspergillus sp. inoculated plants. Beside, the endophytes investigated in this work, increased antioxidant property of leaf extract, but have no effect on content of phenolics compounds and flavonoids. The results of this study clearly indicate the possibility of using bacterial and fungal endophytes for enhancing plant grow