Seed treatment with nano‐iron (III) oxide enhances germination, seeding growth and salinity tolerance of sorghum

Abstract

In recent decades, nanoparticles have been intensively applied in agriculture. Two experiments were carried out to demonstrate the potential of nano‐iron oxide (n‐Fe2O3) as seed treatment (soaking and priming) at different concentrations (0, 10, 50, 100 and 500 mg/L) for enhancing sorghum (Sorghum bicolor (L.) Moench) germination and seedling growth under non‐stressed conditions (Experiment I), and to investigate the impacts of n‐Fe2O3 seed priming treatments (0, 10, 50, 100 and 500 mg/L) on growth, chlorophyll content, chlorophyll a fluorescence, gas exchange, water relations and lipid peroxidation under salt stress (150 mmol NaCl solution) (Experiment II). Results indicated that seed soaking with n‐Fe2O3 at 10 mg/L was the best treatment in improving speed and per cent of germination, while seed priming with n‐Fe2O3 at 50 and 100 mg/L was the most effective treatment in improving seedling (12 days old) growth. Salt stress decreased chlorophyll content, photosynthetic rate, stomatal conductance, transpiration rate, relative water content, osmotic potential and growth, along with increased lipid peroxidation. Among chlorophyll a fluorescence parameters, the photosynthetic performance index of PSII (PIABS) was the most salt‐responsive. Seed priming with n‐Fe2O3 at 500 mg/L increased sorghum growth (45 days old), through increased photosystem II efficiency, chlorophyll index, photosynthetic rate and relative water content with decreased lipid peroxidation. Overall, this study indicated that use of n‐Fe2O3 as a pre‐sowing seed treatment can enhance germination and seedling growth of sorghum and protect from negative impacts of salinity stress.

Impact of Salinity Stress on Membrane Status, Phytohormones, Antioxidant Defense System and Transcript Expression Pattern of Two Contrasting Sorghum Genotypes

“…Salinity stress exacerbates the decomposition of chlorophyll and the ability of a plant to maintain a higher chlorophyll content under salinity stress conditions contributes to salinity stress tolerance. Previous researches have reported a higher chlorophyll content in salinity stress-tolerant sorghum genotypes (Maswada et al, 2018;Mbinda & Kimtai, 2019) and consistent with our data, the higher chlorophyll content in PI 585451 indicates it's salinity stress tolerant ability than PI 585454 and provide insight into the photosynthetic role of the pigment under salinity stress conditions (Fig. 2 C).…”

The efficacy of different seed priming agents for promoting sorghum germination under salt stress

“…Although there are many reports of the beneficial effects of these seed priming methods during salt stress, few studies have investigated whether the above-mentioned agents improve sorghum seed germination under salt stress. Some other priming agents have also been used for this purpose, such as nano-iron oxide [ 32 ], salicylic acid, kinetin and gibberellic acid [ 33 ]. Furthermore, studies comparing the relative effects of different priming agents on sorghum germination under salt stress have rarely been reported.…”

Exogenous jasmonic acid and humic acid increased salinity tolerance of sorghum

“…However, it is susceptible to salt stress at germination, early seedling growth, and reproductive stages. Of these stages, germination is essential to ensure early seedling growth and crop establishment, which places a solid foundation for high crop productivity (Maswada, Djanaguiraman, & Prasad, ).…”