Alleviation of drought stress on rose geranium [Pelargonium graveolens (L.) Herit.] in terms of antioxidant activity and secondarymetabolites by mycorrhizal inoculation
Amiri, A. A. Nikbakhtand . N. Etemadi.2015. Alleviation of drought stress on rose geranium [Pelargonium graveolens (L.) Herit.] in terms of antioxidant activity and secondarymetabolites by mycorrhizal inoculation. ScientiaHorticulturae197 : 373–380.
Drought stress is a major problem that suppresses the growth and yield of plants. Certain microorgan-isms, including arbuscular mycorrhizal fungi (AMF), can improve plant resistance against environmentalstresses. The current study was performed to investigate the effectiveness of mycorrhizal inoculation onrose geranium under different irrigation regimes. The experiment was conducted as a factorial exper-iment based on a completely randomized design (CRD) with three irrigation levels, including 100, 75and 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 showedthat root colonization was suppressed in the severe water deficit condition (50% FC). The essential oilcontent 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 thenon-inoculated treatment regardless of water regime. Catalase, ascorbate peroxidase and glutathioneperoxidase 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 signifi-cantly improved compared to that of non-inoculated plants, and all inoculations resulted in lower MDAand H2O2accumulation in plant tissue. In general, the results suggest that rose geranium can be success-fully grown in areas with limited available water and that AMF can be employed to grow this plant underwater stress conditions to alleviate the adverse effects of water stress