| Abstract: | Compounds that promoted the growth of pollen tubes were isolated from the style of Rhododendron mucronatum and were identified as azalein, (+)-catechin, and (?)epicatechin. Among these compounds, 50–100 ppm of (+)-catechin or (?)-epicatechin increased the growth of pollen tubes in Camelliajaponica, R. mucronatum, Styrax japonica, and Pinus densijlora by 16–20%. These compounds had no significant effects on the growth of pollen tubes in Lilium auratum and Narcissus pseudo-narcissus. Among the phenolic compounds with similar chemical structures as the promoters, catechol-and pyrogallol-type compounds had the activity and the latter types were more effective. As α-tocopherol also showed growth promoting activity, it was thought that the antioxidative activity of the phenolic compounds was responsible for the promotion of the pollen tube growth. |
