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A study of raphide microstructure in relation to irritation
Scanning Electron Microscopy
|January 1, 1984
Summary
Plant crystal structures called raphides, specifically their barbs and size, can cause skin irritation. Microstructure and length are key factors, though chemical toxins may also play a role.
Area of Science:
- Plant anatomy
- Botanical toxicology
Background:
- Raphides are needle-shaped crystals found in plant cells.
- Some plants containing raphides are known to cause irritation upon contact.
Purpose of the Study:
- To investigate the relationship between raphide morphology (barbs, grooves, size) and plant-induced irritation.
- To determine if specific microstructural features of raphides correlate with their irritant potential.
Main Methods:
- Examination of raphides from thirty-four plant genera using light and scanning electron microscopy.
- Analysis of literature data for an additional fifteen genera.
- Correlation of raphide characteristics with known irritant properties of the plants.
Main Results:
- Barbs on raphides are associated with irritation in some families (Araceae, Leeaceae) but not others (Vitaceae).
- Grooves on raphides show an inconsistent association with irritation.
- Raphides without barbs or grooves cause irritation only if they exceed 180 microns in length.
Conclusions:
- Both raphide microstructure (presence of barbs/grooves) and size contribute to plant-induced irritation.
- The inconsistent association of barbs and grooves suggests that other factors, potentially chemical toxins, may also be involved in plant irritation.