Seed micromorphology and calcium oxalate crystal characterization as taxonomic traits in selected species of the genus Impatiens L.

The study analyzed seeds of 12 Impatiens species from Europe, America, and Asia. Scanning electron microscopy (SEM), light microscopy, and confocal microscopy were used to analyze the micromorphology of the seed coat and the morphology of calcium oxalate crystals. A literature review revealed a lack of detailed carpological data for the studied species and a lack of information on the morphology of calcium oxalate crystals in seeds. The results revealed significant interspecific variation in seed surface characteristics, including seed shape, testal cell arrangement, and anticlinal and periclinal wall patterns. A wide variety of surface sculpture types was observed among the analyzed species. Furthermore, calcium oxalate crystals in the form of raphides were observed in all the studied species. The presence of raphides in species from three continents suggests that this may be a characteristic feature of the Impatiens genus, although it is insufficient to distinguish individual species.