Perianth organs in Nymphaeaceae: comparative study on epidermal and structural characters

Area of Science:

• Plant Morphology
• Evolutionary Biology
• Angiosperm Phylogeny

Background:

• The Nymphaeaceae family, including genera like Euryale, Nymphaea, and Victoria, presents diverse perianth structures.
• Understanding perianth differentiation is crucial for deciphering angiosperm evolutionary history.

Purpose of the Study:

• To investigate the differentiation of perianth organs in Nymphaeaceae species.
• To determine the presence and distribution of sepaloid and petaloid characters within tepal whorls and individual tepals.
• To evaluate the evolutionary implications for the mosaic model of perianth development.

Main Methods:

• Macroscopical, light microscopy, and scanning electron microscopy of perianth organs.
• Histochemical detection of osmophores using neutral red and Sudan stains.
• Analysis of epidermal micromorphology, stomata, and hydropotes.

Main Results:

• Outer tepals primarily exhibit sepaloid characteristics with photosynthetic and protective functions.
• The second tepal series displays a mix of sepaloid and petaloid features, indicating a transitional role.
• The innermost tepals are predominantly petaloid, with distinct cuticular ornamentation patterns observed among species.

Conclusions:

• Tepals within Nymphaeaceae species can co-express both sepaloid and petaloid features.
• Findings support the mosaic model of perianth evolution in angiosperms.
• Epidermal morphology correlates with molecular phylogeny, offering insights into Nymphaeaceae evolution.