Exposure to TiO<sub>2</sub> nanoparticles improves the physiological characteristics of drought‐challenged chickpeas (<scp><i>Cicer arietinum</i></scp> L.)
Roya Ghorbani, Ali Ganjeali, Ali Movafeghi, Jafar Nabati
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.