Investigating the Impact of Magnesium on Moehringia Macrophylla, a Serpentine-Tolerant Species

Abstract

Moehringia macrophylla Hook. (Fenzl) (large-leaved sandwort) is an understudied species of the Caryophyllaceae family that shows tolerance to serpentine soil and is rare in New England. Serpentine soils are nutrient-poor and metal-rich, and produce “serpentine syndrome,” or decreased growth and tissue necrosis, in plants growing on it. As the specific mechanisms of M. macrophylla’s response to serpentine conditions are largely unknown, I tested how its growth and cellular accumulation of magnesium were altered by elevated magnesium exposure, a key stressful feature of serpentine environments. I optimized a germination procedure, grew the plant on substrates containing magnesium, and performed confocal microscopy using a magnesium-binding fluorescent dye to determine if and where magnesium localization occurs in the roots, stems, and leaves of this species. Examining the effects of magnesium in M. macrophylla is essential to understanding the mechanisms of tolerance this species employs, and if it follows expected morphological and physiological characteristics for serpentine tolerators. My study establishes a basic understanding of serpentine response, setting the stage for further research on the genetic mechanisms of serpentine tolerance and the impact of the serpentine habitat on the rarity of this species, as well as the possible role of ecotypic differentiation in M. macrophylla.