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

Javad Faraji,Ali Sepehri

doi:10.1590/2317-1545v41n3213139

Abstract

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.

Highlights

Titanium is the ninth most abundant element in the earth’s crust (Feizi et al, 2012)
Application of different concentrations of TiO2 NPs and sodium nitroprusside (SNP) alone or in combination, significantly improved seed germination percentage up to 15% and 23.72% under moderate (-0.4 MPa) and severe (-0.8 MPa) drought stress stimulated by polyethylene glycol (PEG) solutions (Figure 1A)
Our results showed that application of SNP alone or in combination with different concentrations of TiO2 NPs promoted seed germination and early growth of wheat under control condition and drought stress created by PEG solutions (Figures 1 and 2)

Summary

Introduction

Titanium is the ninth most abundant element in the earth’s crust (Feizi et al, 2012). TiO2 NPs have been reported to enhance seed germination and plant growth. Feizi et al (2013) proved that germination rate, germination percentage, germination value, mean daily germination, vigor index and shoot dry weight of fennel seeds were considerably improved upon exposure to TiO2 NPs. In an earlier study they demonstrated that application of TiO2 NPs improved wheat seed germination indices but only mean germination time was significantly affected by TiO2 NPs compared to untreated control (Feizi et al, 2012). Mahmoodzadeh and Aghili (2014) concluded that TiO2 NPs even in high concentrations promoted seed germination and seedling growth of wheat compared to untreated control while low concentrations had inhibitory effects on wheat germination indices. It was observed that exposure to TiO2 NPs improved germination percentage, germination rate, root and shoot length, fresh weight, vigor index and the chlorophyll content of the parsley seedlings (Dehkourdi and Mosavi, 2013)

Methods

Results

Conclusion