An Assessment of the Effective Pollination Period and Its Main Limiting Factor in Wurfbainia villosa var. villosa (Lour.) Škorničk. & A. D. Poulsen (Zingiberaceae)

Low fruit set in <i>Wurfbainia villosa</i> var. <i>villosa</i> has been a major constraint in its cultivation, with the effective pollination period (EPP) identified as a key factor. In this study, the EPP was assessed for the first time by examining stigma receptivity, style suitability, pollen tube growth rate, and ovule longevity, determined by fluorescence emission microscopy, along with initial fruit set (IFS) determined by sequential hand-pollination of flowers of two cultivars of <i>W. villosa</i> var. <i>villosa</i> under field conditions in Xishuangbanna, South China, in 2022 and 2023. The results showed that the inner surface of the stigma is the receptive region, with receptivity lasting more than three days, as confirmed by pollen adhesion and pollen germination. Style suitability, determined by successful pollen tube entry into the ovule, was maintained for two days; most pollen tubes reached the ovules within one day when stigma receptivity was highest. Ovule longevity persisted for at least three days. The IFS was highest when pollinated at 0-1 days after anthesis (DAA) but dropped sharply to near 0% by 2 DAA. Both EPP estimates, based on its components and IFS, indicated that the EPP is two days, with style suitability being the primary limiting factor.