Flavonoids in selected Primula spp.: bridging micromorphology with chemodiversity.

Area of Science:

• Plant biology
• Biochemistry
• Chemical ecology

Background:

• Glandular trichomes in plants are crucial for defense and interaction with the environment.
• Flavonoids, important plant secondary metabolites, are often found in glandular trichomes.
• Understanding flavonoid localization and biosynthesis in trichomes is key to plant chemical diversity.

Purpose of the Study:

• To compare the micromorphology and flavonoid chemistry of glandular trichomes in Primula vialii and Primula vulgaris.
• To investigate the auto-fluorescent properties and localization of flavonoids within these glandular structures.
• To elucidate the origin and transport of flavonoids in relation to glandular trichome differentiation.

Main Methods:

• Epifluorescence microscopy was employed to visualize flavonoid auto-fluorescence and localization.
• Micromorphological analysis of glandular trichomes was performed for both species.
• Chemical analysis, including NMR and mass spectrometry, was used to identify isolated compounds.

Main Results:

• Significant differences were observed in glandular trichome morphology and exudate flavonoid composition between P. vialii and P. vulgaris.
• P. vialii and some subgen. Primula species showed uniform glandular fluorescence, unlike the differentiated fluorescence in P. vulgaris leaves.
• A novel glycoside, kaempferol 3-O-(2''-rhamnosyl)-robinobioside, was isolated from P. vialii leaf tissue, indicating localized biosynthesis.

Conclusions:

• Flavonoids are likely synthesized within the glandular trichomes, not transported from the leaf tissue.
• Chemical diversity in Primula glandular trichomes correlates with structural and tissue differentiation.
• Further research into tissue-specific flavonoid biosynthesis can explain diversification patterns in Primula.