Do selenium hyperaccumulators affect selenium speciation in neighboring plants and soil? An X-Ray Microprobe...

Area of Science:

• Environmental Science
• Biogeochemistry
• Plant Biology

Background:

• Selenium (Se) hyperaccumulators are known to elevate Se levels in neighboring plants.
• The impact of Se hyperaccumulators on Se localization and speciation in surrounding soil and plants remains under investigation.

Purpose of the Study:

• To investigate the effect of Se hyperaccumulators on Se localization and speciation in neighboring plants and soil.
• To determine if Se hyperaccumulators alter the chemical forms of Se in the surrounding environment.

Main Methods:

• X-ray fluorescence mapping and X-ray absorption near-edge structure spectroscopy were employed.
• Se localization and speciation were analyzed in the leaves of Artemisia ludoviciana, Symphyotrichum ericoides, and Chenopodium album.
• Analysis was conducted on plants growing adjacent to both Se hyperaccumulators and non-accumulator species at a seleniferous site.

Main Results:

• Neighboring plants (A. ludoviciana, S. ericoides, C. album) predominantly accumulated reduced selenocompounds (73-92%), with XANES spectra resembling C-Se-C compounds like selenomethionine.
• Preliminary soil analysis indicated that the largest Se fraction (65-75%) was reduced Se, with spectra similar to C-Se-C standards, regardless of whether it was near a hyperaccumulator or non-accumulator species.
• The identified C-Se-C forms in neighboring plants and soil were consistent with those found in hyperaccumulators.

Conclusions:

• Hyperaccumulator litter may contribute organic soil Se, but soil microorganisms are also potential sources.
• The accumulation of organic Se by plants is significant for phytoremediation and biofortification strategies.
• Understanding Se speciation is crucial for optimizing Se uptake in plants for both environmental and nutritional applications.