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

TL;DR

This study examines seed micromorphology and calcium oxalate crystals in 12 Impatiens species to identify taxonomic traits.

Contribution

The study provides the first detailed analysis of seed coat micromorphology and calcium oxalate crystal morphology in these Impatiens species.

Findings

Significant interspecific variation was found in seed surface characteristics like shape and cell arrangement.

A wide variety of surface sculpture types was observed among the species.

Calcium oxalate raphides were present in all species, suggesting a genus-wide trait.

Abstract

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.

The online version contains supplementary material available at 10.1038/s41598-026-36206-w.

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