Pollination mechanisms of Sarcandra glabra, Chloranthus serratus and C.fortunei

2000 Fiscal Year Final Research Report Summary

• Project/Area Number: 10640680
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: 系統・分類
• Research Institution: Gifu University
• Principal Investigator: TAKAHASHI Hiroshi Faculty of Education, Gifu University, Professor, 教育学部, 教授 (40021331)
• Co-Investigator(Kenkyū-buntansha): YAMAUCHI Katsusuke Faculty of Education, Gifu University, Professor, 教育学部, 教授 (30021322)
• Project Period (FY): 1998 – 2000
• Keywords: pollination mechanism / Sarcandra glabra / Chloranthus serratus / Chloranthus fortunei / primitive angiopserms / self-compatibility / beetles / thrips

Research Abstract

Pollination biological studies were conducted in some Japanese populations of Sarcandra glabra, Chloranthus serratus, C.fortunei and C.japonicus. The bracts of C.fortunei appear to have a function supporting the androecium with broad base and long lobes, although those of S.glabra and C.serratus may have a protective function. The bracts of C.japonicus are very small and appear to have neither supporting nor protective function. Although the flowers of all species are protogynous, the stigmas are receptive at least for a few days after pollen-sac dehiscence. A small amount of liquid is secreted in many points mainly on the upper part of the pistil while the stigma is receptive. All species are self-compatible. The flowers of S.glabra were visited by small beetles, bees and syrphid flies. Beetles visit both the flowers just before anther dehiscence and the flowers after anther dehiscence. They appear to probe the liquids on the pistil in the female-stage flowers, and forage for pollen i n the syncmous-stage flowers. The beetles very often touch the stigmas, and seem to be pollinators effective for cross-pollination. Bees forage usually for pollen in the flowers with open anther, and appear to pollinate effectively the syncmous-stage flowers. Syrphid flies foraged for pollen and also licked the ovary, but occasionally touched the stigmas. The flowers of C.japonicus were also visited by small beetles, bees and flies. The most abundant visitors were bees and flies. They visited both the female-stage flowers and the syncmous-stage ones, and very often touch the stigmas while they actively move on the inflorescence. Small beetles appeared to be effective pollinators in the flowers of C.japonicus, although their visitation frequency was low. The flowers of C.serratus were visited by small beetles, syrphid flies, thrips and ants.Thrips enter a small space between the androecium and the inflorescence axis, and much pollen is deposited on the body when they visit the synacmous-stage flowers. The flowers of C.fortunei were visited and appeared to be effectively pollinated mainly by thrips. The flower of all species absorb much UV light.