Floral scent in natural hybrids of Ipomopsis (Polemoniaceae) and their parental species
Floral scent in natural hybrids of Ipomopsis (Polemoniaceae) and their parental species
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DOI：
10.1093/aob/mct279
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发表时间：
2014-02-01
期刊：
影响因子：
4.2
通讯作者：
Campbell, Diane R.
中科院分区：
文献类型：
--
作者：
Bischoff, Mascha;Juergens, Andreas;Campbell, Diane R.
花的性状，如花挥发物，可以促进种特异性传粉者觅食的合子前生殖隔离。当杂交区形成时，花部性状也会影响合子后隔离。本研究通过对亲本和自然杂交种花挥发物的分析，探讨了合子前和合子后分离的潜在气味调节作用。tenuituba及其自然杂种在两个接触点的杂交率和时间觅食模式的不同。利用气相色谱-质谱联用技术对昼夜气味样品中的挥发性成分进行了定量分析，结果表明，亲本和杂交种的挥发性成分在定性上存在重叠。所有的花发出类似的单萜类，倍半萜类，脂肪族和苯类化合物的集合，但分为定量排放的多变量分析所定义的组。亲本物种之间最显着的差异在于含氮化合物吲哚，这种化合物几乎只存在于夜间开花的I。tenuituba。自然杂交花束是高度可变的，并表现出几种化合物的排放率，出现超越。然而，吲哚排放率是中间的杂交种相比，在父母的利率。在低杂交接触点的挥发性花束并没有表现出更大的物种特异性的整体气味排放，但I。细管属植物在天蛾活动高峰期发出吲哚信号，而两种拟牵牛花在开花模式上存在差异，吲哚在夜间释放。tenuituba，但不是在I.聚集体自然杂交花束不一致的父母之间的中间，虽然杂种中间吲哚排放。吲哚信号可能作为一个潜在的天蛾引诱剂，介导的生殖隔离之前和之后的杂交形成。
Floral traits, such as floral volatiles, can contribute to pre-zygotic reproductive isolation by promoting species-specific pollinator foraging. When hybrid zones form, floral traits could also influence post-zygotic isolation. This study examined floral volatiles in parental species and natural hybrids in order to explore potential scent mediation of pre-zygotic and post-zygotic isolation.Floral bouquets were analysed for the sister species Ipomopsis aggregata and I. tenuituba and their natural hybrids at two contact sites differing in both hybridization rate and temporal foraging pattern of hawkmoth pollinators. Floral volatiles were quantified in diurnal and nocturnal scent samples using gas chromatographymass spectrometry.The bouquets of parental species and hybrids showed qualitative overlap. All flowers emitted similar sets of monoterpenoid, sesquiterpenoid, aliphatic and benzenoid compounds, but separated into groups defined by multivariate analysis of quantitative emissions. The parental species differed most strikingly in the nitrogenous compound indole, which was found almost exclusively in nocturnal bouquets of I. tenuituba. Natural hybrid bouquets were highly variable, and showed emission rates of several compounds that appeared transgressive. However, indole emission rates were intermediate in the hybrids compared with rates in the parents. Volatile bouquets at the contact site with lower hybridization did not show greater species specificity in overall scent emission, but I. tenuituba presented a stronger indole signal during peak hawkmoth activity at that site.The two species of Ipomopsis differed in patterns of floral bouquets, with indole emitted in nocturnal I. tenuituba, but not in I. aggregata. Natural hybrid bouquets were not consistently intermediate between the parents, although hybrids were intermediate in indole emission. The indole signal could potentially serve as a hawkmoth attractant that mediates reproductive isolation both before and after hybrid formation.