Silicon and thiourea synergy boosts wheat cultivars' grain quality under salinity via coordinated ion and antioxidant responses

Elahe Gheisary; Seyed Abdolreza Kazemeini; Maryam Samadi; Mozhgan Alinia

doi:10.1038/s41598-025-18660-0

Silicon and thiourea synergy boosts wheat cultivars' grain quality under salinity via coordinated ion and antioxidant responses

Sci Rep. 2025 Oct 7;15(1):34911. doi: 10.1038/s41598-025-18660-0.

Authors

Elahe Gheisary¹, Seyed Abdolreza Kazemeini², Maryam Samadi¹, Mozhgan Alinia³

Affiliations

¹ Department of Plant Production and Genetics, Shiraz University, Shiraz, 71441-13131, Iran.
² Department of Plant Production and Genetics, Shiraz University, Shiraz, 71441-13131, Iran. akazemeini@shirazu.ac.ir.
³ Department of Plant Production and Genetics, Shiraz University, Shiraz, 71441-13131, Iran. mozhgan.alinia@gmail.com.

Abstract

Salinity stress severely impacts wheat productivity and grain quality. This study investigated the effects of application of plant growth promoting substances (non-primed control (NP), hydropriming (HP), combined priming (1 mM silicon + 250 mg L^{- 1} thiourea) (SiP + TUP), combined TU priming (250 mg L^{- 1} thiourea) + Si foliar application (1 mM silicon) (TUP + SiF), combined TU foliar application (250 mg L^{- 1} thiourea) + Si priming (1 mM silicon) (TUF + SiP) on salt tolerance and grain quality of two wheat cultivars (salt-tolerant Barzegar and salt-sensitive Amin) under three salinity levels (0.5, 4 and 10 dS m^{- 1}). The experiment used a completely randomized factorial design with three replications under greenhouse conditions. Salinity reduced grain yield by 42-60% (more severely in Amin), decreased ash content, moisture, carbohydrates, fiber, and gluten, while increasing grain hardness and protein. The combined TUP + SiF treatment significantly mitigated these effects, particularly in Barzegar, restoring 10.5-39.0% of yield versus 34.4-50.0% in Amin. Mechanistically, the treatment: (1) enhanced K⁺/Na⁺ ratio (1.7-2.2-fold) via upregulation of transporters, (2) reduced oxidative damage (MDA decreased by 33.8-60.9%) through boosted antioxidant enzymes (SOD 12-14%, POD 33%, APX 25-26%, CAT 55-94%), and (3) improved grain quality by increasing gluten (8.8-9.8%) and carbohydrates (6.7-7.5%) while reducing hardness and protein. Silicon's role in epidermal silica deposition reduced Na⁺ uptake, while thiourea's thiol group directly scavenged ROS. Cultivar differences revealed Barzegar's superior ion homeostasis and antioxidant capacity. The TUP + SiF combination effectively counters salinity impacts through synergistic physiological mechanisms, with greater efficacy in tolerant cultivar. These findings provide practical strategies for wheat cultivation in saline soils, though cultivar-specific optimization may enhance results.

Keywords: Antioxidant capacity; Grain quality; Ion homeostasis; Salinity stress; Wheat cultivars.

MeSH terms

Antioxidants* / metabolism
Edible Grain* / drug effects
Edible Grain* / metabolism
Ions / metabolism
Salinity
Salt Stress
Salt Tolerance / drug effects
Silicon* / pharmacology
Thiourea* / pharmacology
Triticum* / drug effects
Triticum* / growth & development
Triticum* / metabolism

Substances

Thiourea
Silicon
Antioxidants
Ions