Ms. Donia Khoury - M.Sc. Candidate
18/10/2026
David Wang Auditorium, 3rd Floor, Dalia Maydan Bldg.
13:30
Calcium oxalate (CaOx) is the most common biomineral found in plants, crystallizing as either a monohydrate or dihydrate structure, demonstrating versatile functions in calcium regulation, detoxification of metals from the soil and environment, as well as impairing mechanical strength. While other Ca-bearing minerals like calcium carbonate are known to incorporate different metals, only a limited number of studies have examined metal incorporation in synthetic CaOx and even fewer in biogenic systems. In particular, the aquatic plant Lemna minor forms CaOx raphides and is widely used in remediating polluted wetlands, raising its potential as a biomineralization model for studying metal incorporation into biogenic CaOx.
In this study, we investigated the effects of exposing biogenic CaOx to different metals, specifically Zn, Ba, Cu, Mn, and Sr, while focusing on Sr incorporation into both biogenic and synthetic CaOx. Lemna minor plants were grown in modified Hoagland solutions containing varying Sr:Ca ratios. The extracted CaOx raphides were analyzed for crystal structure, morphology, phase composition, amorphous to crystalline transition, and mechanical properties as a function of incorporated Sr concentration. In parallel, synthetic Sr-doped calcium oxalate was also prepared and investigated for comparison in terms of morphology, phase composition and lattice distortions.
Our findings show that the biogenic CaOx raphides successfully accommodate Sr within a specific concentration range before reaching a limit, modifying their morphology and structure while maintaining the initial amorphous phase. Moreover, this study demonstrates the differences between biologically controlled and synthetic crystallization, highlighting the ability of biological systems to regulate mineral formation under chemically altered environments.