Department of Biological Sciences University of Cincinnati Cincinnati, Ohio 45221-0006.
Am J Bot. 2009 Jul;96(7):1337-47. doi: 10.3732/ajb.0800319. Epub 2009 Jun 10.
Studies of mycoheterotrophs, defined as plants that obtain carbon resources from associated mycorrhizal fungi, have fundamentally contributed to our understanding of the importance and complexity of symbiotic ecological interactions. However, to date, the reproductive ecology of these organisms remains empirically understudied, with existing literature presenting hypotheses about traits including a generalist pollination syndrome and autogamous self-pollination. To address this gap in our knowledge of the reproductive ecology of mycoheterotrophic plants, we comparatively analyzed three species of two monotropoid genera, Monotropa and Monotropsis. During three consecutive years of field observations and manipulations of four populations of Monotropa uniflora, seven of M. hypopitys (both red and yellow color forms), and two of Monotropsis odorata, we investigated flowering phenology, pollination ecology, breeding system, floral herbivory, and reproductive effort and output. Contrary to previous predictions, our results revealed that taxa are largely outcross-pollinated and specialized toward Bombus pollinators. Additionally, species differ in breeding system, timing and duration of reproductive development, fluctuations in reproductive effort and output, and fitness impacts of herbivory. This study is the first thorough investigation of the reproductive ecology of mycoheterotrophic species and provides insight into possible limitations in reproductive traits imposed by a mycoheterotrophic life history.
对菌根异养植物（定义为从相关菌根真菌中获取碳资源的植物）的研究从根本上促进了我们对共生生态相互作用的重要性和复杂性的理解。然而，迄今为止，这些生物体的繁殖生态学在经验上仍未得到充分研究，现有文献提出了关于特征的假设，包括一般性授粉综合征和自交自花授粉。为了填补我们对菌根异养植物繁殖生态学的知识空白，我们比较分析了两个单型属 Monotropa 和 Monotropsis 的三个种。在连续三年的野外观察和对四个 Monotropa uniflora 种群、七个 M. hypopitys（红色和黄色两种颜色形式）和两个 Monotropsis odorata 种群的操作中，我们调查了开花物候、传粉生态学、繁殖系统、花卉草食性以及生殖投入和产出。与之前的预测相反，我们的结果表明，这些类群主要是异花授粉的，并且专门针对 Bombus 授粉者。此外，物种在繁殖系统、生殖发育的时间和持续时间、生殖投入和产出的波动以及草食性对适应性的影响方面存在差异。这项研究是对菌根异养物种繁殖生态学的首次全面调查，为菌根异养生活史所带来的繁殖特征的可能限制提供了深入了解。
