Ameliorative effects of TiO2 nanoparticles and sodium nitroprusside on seed germination and seedling growth of wheat under PEG-stimulated drought stress

Abstract

Seed germination and early seedling growth are sensitive to drought stress in wheat. A factorial experiment was arranged based on a completely randomized design with three replicates to study the impacts of TiO2 nanoparticles (TiO2 NPs: 0, 500, 1000 and 2000 mg.L) and sodium nitroprusside (SNP: 0 and 100 μM), as NO donor, on seed germination and seedling growth of wheat under polyethylene glycol (PEG)-induced drought stress (0, -0.4 and -0.8 MPa). Our results revealed that PEG-stimulated drought stress significantly decreased germination percentage (GP), germination energy (GE), germination rate (GR), root length (RL), shoot length (SL), root fresh weight (RFW), shoot fresh weight (SFW) and vigor index (VI) but increased mean germination time (MGT) in wheat seeds. However, application of TiO2 NPs and SNP alone or in combination significantly enhanced GP, GE, GR, RL, SL, RFW, SFW and VI up to 23.72%, 50%, 33.74%, 85.38%, 93.28%, 73%, 91.91% and 91.04% respectively, but significantly reduced MGT up to 28.36% under severe drought stress. Our results showed that application of TiO2 NPs and SNP alone or in combination can significantly alleviate the adverse effects of PEG-stimulated drought stress on seed germination and early seedling growth of wheat.

Alleviation of nitrogen stress in rice (Oryza sativa) by ceria nanoparticles

“…10 Many studies have shown that nanomaterials may also enhance the tolerance of plants to external stresses such as drought, flooding, cold, heat, salinity and heavy metal stress. 11 For example, TiO 2 NPs have been reported to improve plant growth under drought 12 or cold 13 stress. CuO NPs as low as 1 mg L −1 can enhance the tolerance to pathogens of tomato grown in soil infested with Fusarium oxysporum.…”

Does nitric oxide protect Eucalyptus urophylla seeds under salt stress conditions?

“…Thus, the SNP may have Journal of Seed Science, v.42, e202042041, 2020 induced breakdown of the superoxide ion, eliminating the reactive oxygen species produced and reducing oxidation. Yet, it is possible that the oxygen produced in this process may also have been consumed in respiration, affecting seed metabolic activity and, consequently, increasing germination percentage (Faraji and Sepehri, 2019).…”

“…The increase in root size when the seeds are primed with SNP can be explained through the idea that it performs a role similar to plant hormones, such as cytokinins, gibberellin, and auxin, due to an ability of inducing cell division and proliferation of the plant, as well as tissue differentiation. Salt stress may also have brought about relaxation of the cell wall and induction of cell extension, which consequently has a greater contact surface for absorption of water and greater ability to take up oxygen released by the product during priming (Faraji and Sepehri, 2019).…”

“…The development of total seedling size observed in the treatments in which seeds were previously primed with SNP is due to capture and transport of mineral elements and also to stimulation of molecules that carry water during stress conditions, resulting in greater plant growth (Faraji and Sepehri, 2019).…”

“…Nitric oxide (NO) is an endogenous signaling molecule that plays a fundamental role in the germination of seeds of different species under these conditions. Many studies suggest that application of exogenous NO in the form of sodium nitroprusside (SNP), as NO donor, is involved in an increase in plant tolerance to abiotic stress (Faraji and Sepehri, 2019).…”