Exposure to TiO2 nanoparticles improves the physiological characteristics of drought‐challenged chickpeas (Cicer arietinum L.)

Abstract

Abstract Drought stress markedly affects plant growth and crop production. In turn, treatment with some metal‐based nanoparticles (NPs) such as TiO 2 ‐NPs could improve the plant tolerance against drought stress. In the present study, the effects of different levels of moisture regime (40%, 60%, and 90% field capacity [FC]) in conjunction with various concentrations of TiO 2 ‐NPs (0, 5, 10, 20, and 40 mg. L −1 ) on chickpea were studied. Exposure of drought‐challenged chickpea plants to TiO 2 ‐NPs raised antioxidant enzyme activity compared with plants grown under drought without TiO 2 ‐NP treatment. The highest activity of ascorbate peroxidase (APX) was observed at 40% FC and application of 40 mg. L −1 TiO 2 ‐NPs. Moreover, peroxidase (POX) activity has increased with the enhancing concentration of TiO 2 ‐NPs to 20 mg. L −1 at 90% FC. In comparison, the application of 40 mg. L −1 TiO 2 ‐NPs and decreasing levels of FC caused a rise in the activity of superoxide dismutase (SOD). Exposure to TiO 2 ‐NPs raised the amount of total phenols and 2,2‐diphenyl‐1‐picryl‐hydrazyl‐hydrate (DPPH) at different levels of moisture regime. The content of malondialdehyde (MDA) at 60% FC has decreased by 22% after treatment with 20 mg. L −1 TiO 2 ‐NPs compared with control plants. Also, treatment with TiO 2 ‐NPs heightened the proline content, and the highest amount of proline was obtained at 40% FC by applying 20 mg. L −1 NPs. The treatment with TiO 2 ‐NPs in the moisture regimes led to higher chlorophyll and carotenoid production in chickpea plants. Taken together, the application of TiO 2 ‐NPs could raise the defense potential of chickpea plants against oxidative stress caused by the generation of reactive oxygen species.