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

两种自然杂交的淫羊藿和E. sempervirens（小檗科）之间的生殖隔离机制

• 批准号: 13640691
• 负责人: MAKI Masayuki
• 金额: $ 2.18万
• 依托单位: Tohoku University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2001
• 资助国家: 日本
• 起止时间: 2001 至 2002
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-13640691/
• 关键词: Epimedium; E.diphyllum; E.sempervirens; pollen germination; pollen tube growth; reproductive isolation; hybrid zone; molecular phylogeny; マイクロサテライトDNA; メギ科; 花粉管競争; DNAマイクロサテライト; イカリソウ屬

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.

研究了两个自然杂交的二叶淫羊藿属和半叶淫羊藿属植物之间的生殖隔离。在田间观察中，虽然欧洲野龙须草开花稍早于二叶龙须草，但其开花季节隔离很弱。季节隔离似乎对这两个杂交物种之间的生殖隔离没有作用。在人工杂交试验中，种内杂交和种间杂交的花粉萌发率差异不显著。种内杂交和种间杂交的花粉管生长也没有显著差异，但种内杂交的花粉管生长略大于种间杂交。因此，花粉萌发和花粉管生长的阶段似乎也不利于这两个物种之间的生殖隔离。此外，还对日本淫羊藿属进行了分子系统发育分析。在叶绿体DNA的系统发育树中，两个种分属不同的分支，表明这两个物种相互联系，形成了杂交带。在18S-26S rDNA ITS区和Ets区的系统发育树中，由于缺乏变异，淫羊藿属植物的系统发育尚未完全解决。