臺灣產月桃屬 (薑科) 物候與授粉生態

Abstract

Flexistylous Alpinia have two kinds of individuals with different flowering behaviors. The anaflexistylous morph respectively plays the role of male and female in the morning and afternoon, and cataflexistylous morph vice versa. There are rich and various Alpinia resource, but no related researches of flowering behaviours in Taiwan. This study investigated the newborn pseudostems sprouting pattern, the sequence of antheses in time, the flowering behaviours, and the floral visitors composition of Alpinia taxa in Taiwan; and discussed the phenology and pollination ecology of natural A. shimadae var. kawakamii population deeply. Taiwanese Alpinia sprout pseudostems in most months, the changing amount of pseudostems divide into three types: first, the number of newborn pseudostems decreases in anthesis or later, and its anthesis tendency toward spring; second, the period of anthesis and large number of pseudostems sprouting are simultaneous in summer; third, the changing amount has no relationship with anthesis and climate. According the timing of antheses, all Taiwanese Alpinia divide into spring, spring/summer, and summer flowering. Taxa distributed in Northern Taiwan are mostly flowering in spring; distributed in Hengchun Peninsula, Lanyu, and originated from South Asia are flowering in summer; distributed in Central Taiwan or widely distributed in Taiwan are flowering in spring or spring/summer. A. shimadae, A. shimadae var. kawakamii, and A. intermedia possess flexistyly, the other taxa can’t be confirmed exactly for only one sample, need further researchs to verify how common flexistyly is in Taiwanese Alpinia. In A. shimadae var. kawakamii, there are pseudostem sprouting in every months except April and May, the changing amount have no significant correlation with meteorological factors, but possibly affected by full blooming and fruit development; the length of pseudostem grows rapidly in initial stage then gradually reducing, the number of leaves steadily increased with time, and both of them have significant positive correlation with the other; the flower buds develop before the next anthesis two months ago when the pseudostems have grown about 200 days, 100 cm of the length, and 10 of leaves, and there are significant positive correlation between the number of flowers and the length of pseudostems; the population's anthesis is in March to May, and it full blossom in April; the inflorescence has 161.2±65.0 flowers, blooms 36.6±9.1 days, and blooms 3.5±2.5 flowers per day. Floral visitors of Taiwanese Alpinia were composed of variable insects, and the members of Apidae among those visitors are effective pollinators of Taiwanese Alpinia, such as Bombus eximius and Amegilla urens. Bombus eximius has higher visiting frequency at early morning and late afternoon, those periods overlapping with sexual phases of Alpinia. The cooperation between the flowering behaviour of Alpinia and the foraging habits of pollinators promotes the efficiency of pollination.