Selenium as a sulphydrylic group inductor in plants

Area of Science:

• Plant Physiology
• Environmental Science
• Biochemistry

Background:

• Non-protein thiol groups, including glutathione, are crucial for plant defense and stress response.
• Selenium is an essential trace element with varying effects on plants depending on its form and concentration.
• Understanding selenium's interaction with plant thiol metabolism is vital for agriculture and human health.

Purpose of the Study:

• To investigate the impact of different selenium forms (selenite and selenate) and doses on total glutathione and non-protein thiol content in spinach and tomato.
• To compare the accumulation of these compounds in different plant organs (roots and shoots) and species.
• To determine the influence of selenium speciation on plant thiol biosynthesis.

Main Methods:

• Hydroponic cultivation of *Spinacia oleracea* (spinach) and *Lycopersicon esculentum* (tomato) plants.
• Application of selenite (Na2SeO3·5H2O) and selenate (Na2SeO4) at varying doses to the nutrient solution.
• Quantification of total glutathione and non-protein thiol (-SH) group content in plant tissues (roots and shoots).

Main Results:

• Selenium supplementation, regardless of form, increased non-protein thiol content in both plant species.
• Non-protein thiol accumulation was dependent on selenium form, dose, plant organ, and species.
• Spinach biomass exhibited higher non-protein thiol content than tomato biomass across all treatments.
• Selenite promoted greater non-protein thiol accumulation in roots, while selenate favored accumulation in shoots.

Conclusions:

• Both selenite and selenate can enhance plant non-protein thiol levels, suggesting a role in mitigating selenium-induced stress.
• Differential accumulation patterns indicate species- and organ-specific responses to selenium speciation.
• The findings provide insights into selenium's biochemical effects in edible plants, with implications for selenium biofortification strategies.