Mechanisms of reproductive isolation between two naturally hybridizing Epimedium diphyllum and E. sempervirens (Berberdiaceae)

2002 Fiscal Year Final Research Report Summary

• Project/Area Number: 13640691
• 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: Tohoku University
• Principal Investigator: MAKI Masayuki Tohoku University, Graduate school of Life Sciences, Associate Professor, 大学院・生命科学研究科, 助教授 (60263985)
• Project Period (FY): 2001 – 2002
• Keywords: Epimedium / E.diphyllum / E.sempervirens / pollen germination / pollen tube growth / reproductive isolation / hybrid zone / molecular phylogeny

Research Abstract

Reproductive isolation between two naturally hybridizing Epimedium diphyllum and E. sempervires (Berberidaceae) was examined. In field observation, seasonal isolation of flowering was very weak, although E. sempervirens flowered slightly earlier than R diphyllum. The seasonal isolation does not seem to work for reproductive isolation between the two hybridizing species. In artificial crossing experiments, percentage of pollen germination was not different between intra-and interspecific crossing. Pollen tube growth was also not significantly different between intra-and interspecific crossing, although pollen tube growth in intraspecific crossing slightly larger than that in interspecific crossing. Thus, stage of pollen germination and pollen tube growth also does not seem to work for reproductive isolation between the two species. In addition, molecular phylogenetic analyses were done for the Japanese Epimedium. In the phylogenetic tree of chloro plast DNA, E. sempervkens and E. diplyllum belongs to different clades, suggesting that these two species contacted secondary and form the hybrid zone. In the phylogenetic tree of ITS and ETS region of 18S-26S rDNA, the phylogeny of Epimedium species was not fully solved due to scarcity of variation of these regions.