Alleviation of drought stress on rose geranium [Pelargonium graveolens (L.) Herit.] in terms of antioxidant activity and secondary metabolites by mycorrhizal inoculation
Amiri, A. A. Nikbakht and N. Etemadi. 2015. Alleviation of drought stress on rose geranium [Pelargonium graveolens (L.) Herit.] in terms of antioxidant activity and secondary metabolites by mycorrhizal inoculation. Scientia Horticulturae 197: 373–380.
Drought stress is a major problem that suppresses the growth and yield of plants. Certain microorganisms, including arbuscular mycorrhizal fungi (AMF), can improve plant resistance against environmental stresses. The current study was performed to investigate the effectiveness of mycorrhizal inoculation on rose geranium under different irrigation regimes. The experiment was conducted as a factorial experiment based on a completely randomized design (CRD) with three irrigation levels, including 100, 75 and 50% Field Capacity (FC). Mycorrhizal inoculation included Glomus mosseae (Gm), Glomus intraradices (Gi), a combination of both species (Gi + Gm), and a non-inoculated control (NM). The results showed that root colonization was suppressed in the severe water deficit condition (50% FC). The essential oil content significantly increased by 16% when the plants were under moderate water deficit (75% FC) compared to 100% FC. AMF inoculation improved the essential oil content and oil yield compared to the non-inoculated treatment regardless of water regime. Catalase, ascorbate peroxidase and glutathione peroxidase activities reached peak values when plants were under the moderate water deficit condition (75% FC). Regardless of the AMF inoculation treatment, the plant enzymatic defence system was significantly improved compared to that of non-inoculated plants, and all inoculations resulted in lower MDA and H2O2 accumulation in plant tissue. In general, the results suggest that rose geranium can be successfully grown in areas with limited available water and that AMF can be employed to grow this plant under water stress conditions to alleviate the adverse effects of water stress.