Summary. Flavonoid patterr/s of pollens of 5 plants of the family Cucurbitaceae are different from those of the corresponding stigmas. The major flavonoid of pollens has been identified as kaempferol 3-O-rutinoside (1). Rutin (2) has been found in stigmas of 2 species. The other flavonoids of pollens and stigmas of these plants are flavonol 3-O-glycosides.It is well known that the discovery of the functions of flavones and flavonols in plants is perhaps the most interesting problem in flavonoid field. The first evidence that theflavonoids of pollens and stigmas may be connected with sex expression in plants was reported by Barbel a who showed that the anthers and stigmas respectively of male and female flowers of Cucurbita pepo contain different glycosides of different quercetin methyl ethers. However, Hartshorne 3 examined anthocyanins from male and female flowers of several plants and could find no significant differences. Recent results 4 have substantially confirmed the report of Barber and have shown that there are differences between the flavonoid patterns of pollens and corresponding stigmas of 3 other species of the genus Cucurbita (C. maxima, C. moschata and C.ficifolia). Since the above results may be restricted to p!ants of the genus Cucurbita, in the present work the flavonoids of pollens and stigmas of 5 plants (Cucurbitaceae) not belonging to this genus (Lagenaria vulgaris, Cucumis citrullus, Sechium edule, Ecballium elaterium and Bryonia dioica) have been examined. Material and methods. For paper chromatography and TLC the solvent mixtures used were: A) 1-butanol-acetic acidwater (4:1 : 5, upper phase); B) acetic acid-water (5 : 95); C) 1-butanol-ethanol-water (4:1:2,2); D) phenol saturated with water; E) acetic acid-concentrated HCl-water concentrated and rechromatographed in solvents B and C. Flavonoids (table) were characterized by colour reactions, UV-spectral analysis with uSual shift reagents 5, total acid hydroIysis with 2 N HC1 (1 h at 100~ controlled acid hydrolysis with 10% acetic acid (3.5 h under reflux) and Rf data; identifications of 1 and 2 were confirmed by paper co-chromatography with authentic samples (solvents A, B, C and D). Aglycones (kaempferol or quercetin) obtained by total acid hydrolysis were identified by UV-spectral analysis with shift reagents 5, paper co-chromatography with authentic samples (solvents A, C, D and E), SiO 2 TLC (solvent F) and polyamide TLC (solvent G); some flavonoids were not isolated in sufficient amount for total acid hydrolysis but colour reactions (dark to yellow in UV+NH3), UV-spectral properties and Rf data suggested that they are flavonol 3-O-glycosides. The sugars obtained by total acid hydrolysis of kaempferol 3-O-rutinoside and rutin were identified as rhamnose and glucose by paper cochromatography (solvents A and H) and SiO 2 TLC (solvent I); controlled acid hydrolysis of these flavonoids gave rhamnose, glucose and rutinose identified as above. The sugars attached to the other flavonoids were not identified but the Rf data of these compound...
