Purple Cohosh And Dodder Kwai (ranunculaceae) Pollination Biology

Trib. Cimicifugeae is one of the most floral variation groups in Ranunculales. The floral particularity has a mutual adaptation with its pollinators and the phenology. The study of pollination ecology of Trib. Cimicifugeae could provide some perspectives into understanding some key questions about plant evolution, such as adaptive evolution and mating system. The present study focuses on plant-pollinator interaction, floral advertisement and rewards, sex expression characteristics, mating system and the phenology in two species, Cimicifuga purpurea (Hsiao) Park & Lee and Eranthis stellata Maxim., to explore the adaptive evolution and evolutionary trend of honey leaves. In addition, we want to know how to adapt to E. stellata. in the harsh environment of the early spring. The main results are as follows:(1) The results of the pollination biology in C. purpureaC. purpurea blossoms from August to September with 2-4 branches in racemes, and it has a high density of flowers. The individual flower of C. purpurea consists with 6-8 stamens and 1-2 carpels. The purple sepals didn't fully open in florescence, and the sepals restrictions make floral symmetry in approximatem onosymmetric. The P/O is 1845.08. After the anthers dehisce, pollen has been maintain its viability over 90% for 16h. In the individual flower, it is proterandrous and spatial separation, but the period of the stamens and pistils exists a short overlap.The bagging experiments indicate that the apomixes and wind-pollination don't completely exist, and the setting percentage of the self-pollination, hand-pollinated and control groups all exceeds 75%.Vespa rufa. is the most efficient pollinator and outnumbers all the other groups. There are also several secondary pollinators and night pollinators, Apis cerana, flies, syrphidae, and so on. Honey is the main pollination reward. The data indicates that this plant is adapted to the pollination by Vespinae.With the comparison among the results of the pollination biology, mating system exists the transform from self-incompatible to facultative outcrossing in Cimicifuga, which caused by the change of the pollinators.Based on our study results, we agree that Cimicifuga purpurea (Hsiao) Park & Lee become one species, not a variant.(2) The results of the pollination biology in E. stellataE. stellata blossoms in April. The individual flower consists with 15-34 stamens and 4-9 carpels. The sepals, honey leaves and stamens all are white, and there are two bright yellow false nectars on the honey leaf. The P/O is 808.96. It is proterandrous and spatial separation, but the period of the stamens and pistils exists a short overlap.The primary pollinators are Anthomyiidae and Syrphidae, sometimes are flies and Sphecinae. The pollinator visitation frequencies of Anthomyiidae and Syrphidae are extremely high, but carrying powder quantity is not much, which is completely opposite in Milesiinae and Sphecinae. We didn't find honey liquid secretion in nectar leaves, so we presume that the yellow false nectar simulates food sources of the pollinators. For example, honey bead.E. stellata has evolved the unique flowering pattern, generalization pollination system, and characteristics of its breeding system to adapt to the harsh environmental conditions of the early spring. Characteristics of its breeding system, such as self-compatibility and spontaneous self-pollination, can ensure reproductive success even when pollinators are scarce or pollinator visitation frequencies are low.(3) The relationship between the different shapes of nectar leaves and the pollinatorsC. purpurea and E. stellata respectively have different pollinators, Hymenoptear and Diptera. The honey leaves of the two species both are half-hidden, but they hide nectar in different means. The sepals don't fully open in C. purpurea to protect honey from pollinators. Vespa rufa., the primary pollinator in C. purpurea, has strong limbs to help get juices, but flies don't have this ability. Nectar is hidden in the depths of the bi-lamellate honey leaves in E. stellata, but small opening and no obvious liquid secretion didn't attract bees. So E. stellata is food-deceptive pollination.Shape diversification differentiations of the Trib. Cimicifugeae nectar leaves correspond to the choices of pollinators with different pollination efficiency. ie, from Diptera to Hymenoptear.