Silicon-Selenium Interplay Imparts Cadmium Resistance in Wheat through an Up-Regulating Antioxidant System

Area of Science:

• Agricultural Science
• Environmental Science
• Plant Physiology

Background:

• Cadmium (Cd) is a toxic heavy metal that severely impairs plant growth, nutrient uptake, and yield.
• Developing strategies to mitigate Cd toxicity and accumulation in crops like wheat is crucial for food safety.
• Selenium (Se) and Silicon (Si) are known to influence plant responses to stress, but their combined effect on Cd toxicity in wheat requires investigation.

Purpose of the Study:

• To evaluate the comparative effects of Selenium (Se) and Silicon (Si) on wheat growth and antioxidant systems under Cadmium (Cd) stress.
• To investigate the potential of co-applying Se and Si to reduce Cd toxicity, enhance Cd resistance, and improve Se fortification in wheat.
• To elucidate the underlying mechanisms of Cd tolerance and homeostasis influenced by Se and Si supplementation.

Main Methods:

• Wheat plants were grown in a hydroponic system and exposed to 10 µmol Cd.
• Treatments involved root application of 0.2 mmol Si and foliar application of 1.5 µmol Se.
• Evaluated plant biomass, physiological attributes, antioxidant enzyme activities (GSH, GR, APX, CAT), oxidative damage markers (H2O2, MDA), Cd translocation, and nutrient levels.

Main Results:

• Co-application of Se and Si significantly improved wheat biomass and physiological growth under Cd stress.
• Se + Si supplementation enhanced antioxidant enzyme activities and reduced oxidative damage markers (H2O2, MDA) and structural damage.
• Si reduced Cd translocation and accumulation in roots and shoots, while Se primarily mitigated oxidative damage, particularly in shoots. A novel positive correlation between Si and Se uptake was observed.

Conclusions:

• Co-application of Se and Si effectively mitigates Cadmium toxicity in wheat, promoting growth and improving nutritional quality.
• The combined application upregulates the antioxidant system, controls Cd translocation and distribution, and contributes to sulfur (S) homeostasis.
• This strategy offers a potential solution for ensuring food safety in Cadmium-contaminated environments by reducing Cd risk in wheat.