Study the effects of symbiotic microorganisms on growth, percentage and chemical composition of essential oil of Lemon balm (Melissa officinalis L.) under drought stress

Subject Areas : Crop Production Research

ابراهیم اسحقی ¹ , Hormoz Fallah ^{2 *} , Mojgan Niknejad ³ , Davood Barari Tari ⁴

1 - گروه میکروبیولوژی،دانشکده علوم پایه،دانشگاه ازاد قم،قم،ایران
2 - Department of Agronomy, Am.C., Islamic Azad University, Amol, Iran
3 - - Student of Master degree of English language
4 - Department of Agronomy, Am.C., Islamic Azad University, Amol, Iran.

Received: 2024-12-11 Accepted : 2025-03-06 Published : 2025-03-13

Keywords: Azospirillum, Drought stress, Essential oil, lemon balm, Mycorrhiza,

Abstract :

In order to study the effects of the use of symbiotic microorganisms on growth traits, essential oil content and chemical compositions of the essential oil of lemon balm (Mellisa officinalis L.) under drought stress, a factorial experiment was conducted in a completely randomized design with three replications during 2021. Drought stress at two levels (100% field capacity (FC) and 50% FC) as the first factor and seed inoculation with symbiotic microorganisms at four levels (no inoculation, inoculation with Azospirillum brasilense, inoculation with Glomus mosseae and inoculation with A. brasilense + G. mosseae) were considered as the second factor. The results showed that drought stress reduced plant height, number of leaves per plant, concentration of photosynthetic pigments and enhanced the essential oil percentage. Inoculation of symbiotic microorganisms under non-stress conditions did not cause significant changes in the content of photosynthetic pigments, whereas it improved the height and number of leaves per plant. The application of each of the symbiotic microorganisms individually or in combination significantly increased plant height, number of leaves per plant, and photosynthetic pigment content in plants under drought stress. However, simultaneous inoculation of symbiotic microorganisms (bacteria + fungus) resulted in the highest plant height, number of leaves per plant, photosynthetic pigment content, and essential oil percentage under both stress and non-stress conditions. According to the findings of the present study, simultaneous application of plant growth-promoting bacteria and mycorrhizal fungi can help increase growth, improve photosynthetic pigment content, and enhance essential oil percentage of lemon balm under drought stress.