生物多样性 ›› 2017, Vol. 25 ›› Issue (6): 608-614.DOI: 10.17520/biods.2017039

• 研究报告 • 上一篇    下一篇

同域分布共享传粉者的鼠尾草属植物的生殖隔离

魏宇昆*(), 黄艳波, 李桂彬   

  1. 上海辰山植物园, 中国科学院上海辰山植物科学研究中心, 上海 201602
  • 收稿日期:2017-05-27 接受日期:2017-06-21 出版日期:2017-06-20 发布日期:2017-07-10
  • 通讯作者: 魏宇昆
  • 基金资助:
    上海市绿化和市容管理局资助项目(G162408, G172410)

Reproductive isolation in sympatric Salvia species sharing a sole pollinator

Yukun Wei*(), Yanbo Huang, Guibin Li   

  1. Shanghai Chenshan Plant Science Research Center, Chinese Academy of Sciences; Shanghai Chenshan Botanical Garden, Shanghai 201602
  • Received:2017-05-27 Accepted:2017-06-21 Online:2017-06-20 Published:2017-07-10
  • Contact: Wei Yukun

摘要:

生殖隔离是生物多样性产生的重要原因之一, 不同物种间的生殖隔离形成阶段、方式和强度不完全相同。为了揭示生殖隔离在鼠尾草属(Salvia)物种多样性产生和维持过程中的作用和特点, 本文研究了浙江天目山同域分布的舌瓣鼠尾草(S. liguliloba)和南丹参(S. bowleyana)的开花、传粉和生殖隔离, 利用人工授粉和杂交实验检测它们的种间遗传相容程度。结果表明, 在花的形态结构、花及花序的生长、着生方式与数量特征上, 2种鼠尾草属植物均差异显著(P < 0.05)。2种鼠尾草属植物共享同一种有效传粉昆虫——三条熊蜂(Bombus trifasciatus), 但通过访花行为的显著差异和明显不同的花粉落置部位, 有效避免了异源花粉干扰。人工杂交授粉的结果表明2个物种间遗传相容性较高, 互为亲本的杂交结实率分别达到77.8 ± 10.7%和78.7 ± 11.2%。我们的研究表明, 同域分布、花期重叠且共享唯一传粉者的2种鼠尾草属植物, 以花部的传粉结构和传粉部位的差异, 产生了较高程度的传粉前生殖隔离, 避免了物种间的异源花粉干扰和自然杂交, 保障各自较高的繁殖成效, 以维持自然种群的多样性和遗传结构的稳定。

关键词: 机械隔离, 遗传相容性, 物种多样性, 自然杂交, 三条熊蜂

Abstract:

Reproductive isolation (RI) is one of the key factors for speciation and diversity maintenance, however, there are differences in formation stage, means, and strength of RI for different species. To assess the effects and the significance of reproductive isolation in Salvia species, we compared flowering, pollination, and reproduction characteristics of Salvia liguliloba and S. bowleyana, which grow sympatrically and have overlapping flowering periods in the Tianmu Mountain, Zhejiang. Furthermore, artificial hybridization between the two species were conducted to estimate and understand their genetic compatibility and reproductive isolation. Results indicated that the two Salvia species considerably differed in their flower morphological structures, inflorescence organization, and the number of flowers produced per inflorescence. Bombus trifasciatus is the sole pollinator for these two species during the overlapping flowering period. However, different visitation behavior and floral structure (P < 0.05) leads to obviously different pollination patterns between the two species. Pollen is deposited on distinctly separate areas of the pollinator’s body in a manner precluding contact with any heterospecific Salvia stigmata. Under natural condition, the two species are equally successful in reproduction (natural seed set > 87%). Artificial pollination and hybridization experiments between these two species showed that they have a higher genetic compatibility. The cross seed sets are 77.8 ± 10.7% and 78.7 ± 11.2% when the two species are reciprocally cross parents. Our research suggests that for the two Salvia species lacking genetic incompatibility systems and relying on pollinators for outcrossing, there are differences in floral structures and pollen placement sites. The mechanical isolation (a form of pre-pollination RI) prevents heterospecific pollen interference and natural hybridization of the two different species that grow sympatrically and have overlapping flowering periods, and also maintains species diversity and the constancy of species heredity.

Key words: mechanical isolation, genetic compatibility, species diversity, natural hybridization, Bombus trifasciatus