Calcium oxalate druses affect leaf optical properties in selenium-treated Fagopyrum tataricum

Area of Science:

• Plant Science
• Biochemistry
• Optics

Background:

• Plants in the genus Fagopyrum accumulate crystalline calcium oxalate (CaOx) deposits (druses).
• These druses can influence leaf optical characteristics.
• Selenium is known to affect the uptake and accumulation of essential elements like calcium.

Purpose of the Study:

• To investigate if selenium treatment alters CaOx druse numbers in Tartary buckwheat (Fagopyrum tataricum).
• To determine the impact of altered druse numbers on leaf optical properties.

Main Methods:

• Field cultivation of Tartary buckwheat.
• Foliar application of sodium selenate (10 mg Se L⁻¹) or water at the flowering stage.
• Assessment of plant morphology, biochemistry, physiology, optical properties, and leaf elemental composition.
• Redundancy analysis to correlate parameters with spectral data.

Main Results:

• Selenium spraying increased leaf thickness and Se content but decreased CaOx druse density.
• No significant changes in other elemental contents (including total calcium) or leaf biochemical/functional properties were observed.
• CaOx druse density and area were significant factors explaining variability in leaf reflectance and transmittance spectra.
• Druse density positively correlated with reflectance (blue, green, yellow, UV-B); druse area positively correlated with transmittance (green, yellow).

Conclusions:

• Selenium treatment effectively reduces CaOx druse density in Fagopyrum tataricum leaves.
• Changes in CaOx druse density and area significantly impact leaf optical properties, particularly reflectance and transmittance.
• This study establishes a link between selenium-induced modulation of CaOx deposits and plant optical characteristics.