Document Type : Research Paper

Authors

• Ghobad Salimi ¹
• Fatemeh Javadi ²

¹ Department of Biotechnology and Plant breeding, faculty of agriculture, Islamic Azad University, Kermanshah, Iran

² Islamic Azad University Kermanshah Branch

Abstract

Background and purpose: The medicinal plant Ocimum basilicum L. is one of the most important medicinal plants. It is native to tropical regions from Central Africa to Southeast Asia and has antimicrobial, antioxidant, analgesic, and anti-inflammatory properties. Drought stress is one of the most important abiotic factors that can severely affect plant growth and yield. This study aimed to investigate the effect of mycorrhizal fungus on some physiological and biochemical properties of the medicinal plant O. basilicum L. under drought stress.
Methodology: This experiment was conducted in the research greenhouse of Islamic Azad University, Kermanshah branch in 2022. The experiment was performed as a factorial experiment in a Random completely blocked design with two factors (mycorrhiza fungus) in three levels including control (without inoculation with fungus), G. etunicatum and G. mosseae, water drought stress at three levels (without stress, 75 and 50% of field capacity) were performed in four replications. The traits measured in the experiment include, the number of leaves, relative water content, ion leakage, photosynthetic pigments, proline, carbohydrate, antioxidant activity, phenol content and clonization percentage.
Results: The results of analysis of variance analysis showed that the effect of mycorrhizal fungus on all the traits measured in the experiment was significant, and also, the effect of drought stress on all the investigated traits was significant except for the amount of phenol and total chlorophyll. The interaction effect of two factors, mycorrhizal fungus and different levels of drought stress, on the characteristics of ion leakage and carotenoid content was significant. Mean comparisons of data showed that the highest number of leaves  (70.5) was observed in the treatment of G. mosseae fungus, and the lowest number of leaves (58) was in the treatment without fungus. The highest relative water content of leaves (79.059%) was in non-stress conditions, which had a significant difference with the stress conditions of 75 and 50% of crop capacity. The highest electrolyte leakage percentage (33.02%) in the stress condition was 50% of the field capacity in the control treatment, which was not significantly different in the same condition as the G. etunicatum fungus treatment. Inoculation with mycorrhizal fungus increased the content of total chlorophyll so that the highest amount of total chlorophyll (0.96 mg/g of fresh weight) was obtained in the treatment of G. mosseae, which was not significantly different from G. etunicatum and also inoculation with mycorrhizal fungi increased the content of chlorophyll a and b by 91.8%. Inoculation with mycorrhizal fungus increased the proline content by 25.33%, too. The highest antioxidant activity (21.13%) was obtained in treating G. mosseaefungus. The lowest amount of essential oil was observed in the 50% of the field capacity treatment, 25.96% less than the control treatment. Drought stress decreased the percentage of root colonization in G. mosseae by 55.77% and in G. etunicatum by 57.93%.
Conclusion: Mycorrhizal fungus improved the morphological and physiological characteristics in green basil plant.symbiosis with G. mosseae fungus under drought stress conditions with increasing proline and antioxidant activity, improved physiological traits and resistance to drought stress in green basil plant.

Keywords

• Drought stress
• medicinal plant
• colonization percentage
• proline
• essential oil percentage

Main Subjects

• Improvement and breeding