关键词: 华中五味子, 雄花, 花粉形态, 花粉萌发率

Abstract: [Objective] In order to provide a basis for studies of pollination biology and phylogenetic classification of Schisandra sphenanthera by investigating characteristics of the male flowers and their pollen. [Method] We studied the floral characteristics and pollen morphology of S. sphenanthera at different development stages including alabastrum intumescence stage, petals loose stage, petals opening stage and florescence stage using stereo microscope and scanning electron microscope (SEM). In vitro pollen germination of S. sphenanthera was studied using bio-optical microscope and solid agar as culture media containing 10 g·L^-1 agar, and sucrose at concentrations of 50, 100, 150, 200 g·L^-1 in order and boric acid at concentrations of 0.10, 0.15, 0.30 g·L^-1 in order.[Result] The corolla of S. sphenanthera was rose-like and faced downwards the ground when it matured, the petals were arranged in imbrications. The inside and outside of the petals had irregular grains and irregular distribution of stomata, flower stalks were cylindrical and its outside surface was unsmooth with oblong stomata, stamens grew upwards spirally on the columnar receptacle, filaments were shortened to become fleshy and the anthers grew on it. The stamens were arranged in umbrella-form, with a number of 19-22 (26). The pollen was oblate and heteropolar, its polar view was 6-lobed circular, 6 germinal furrows was gradually formed with flower development, of which 3 long furrows joined together at one pole to form an integrated furrow and 3 short ones did not reach the poles, the long and short furrows were alternatively arranged. The extine of pollen had reticular formation with areoles and murus in different sizes, and unclear particles were contained in a few of the areoles. The areoles and the murus respectively became deepened and thinned, and the particles were absorbed with the development of pollen. The diameters at different stages of flower development were 21.96, 23.73, 24.00 and 25.65 μm, respectively. The highest germination rate of mature pollen was 92.6% when cultured in the medium of agar at a concentration of 10 g·L^-1+sucrose at concentration of 100 g·L^-1+boric acid at a concentration of 0.10 g·L^-1, the pollen tubes could reach a length of 454.30 μm. The concentration of sucrose had extremely significant effects on pollen germination rate and elongation of pollen tubes, while the concentration of boric acid had significant effects on pollen germination rate, but not on elongation of pollen tubes.[Conclusion] The corolla form and the pollen morphology of S. sphenanthera had the typical characteristics of insect pollination and wind pollination. The results suggested that S. sphenanthera was not only animal-pollinated but also wind-pollinated, and further studies were needed to identify which was the main pollination model. The best solid media for in vitro pollen germination of S. sphenanthera was 10 g·L^-1 agar+100 g·L^-1 sucrose+0.10 g·L^-1 boric acids, and the medium composition had a significant impact on the germination rate. The germination rate was high, indicating an obvious competitive advantage in pollination and fertilization.

Key words: Schisandra sphenanthera, male flower, pollen morphology, pollen germination rate