Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15260, USA.
New Phytol. 2011 Nov;192(3):738-46. doi: 10.1111/j.1469-8137.2011.03831.x. Epub 2011 Jul 21.
• In natural communities, plants can receive pollen from multiple heterospecifics as well as conspecifics. However, studies on the effects of interspecific pollen transfer have focused on interactions between species pairs. The potential exists for diverse interactions among heterospecific pollen (HP) grains on the stigma, and for these to affect plant reproduction, alone or in combination with conspecific pollen (CP) loss, but these interactions have not yet been explored. • We used hand-pollinations to simulate increasing community diversity and CP loss on Mimulus guttatus stigmas. We used pollen mixes of one to three heterospecific donors to determine how species composition and CP load size affect seed production and to characterize the mechanisms underlying fertilization failure. • Heterospecific pollen deposition reduced M. guttatus seed production and while the effect increased with the number of heterospecific donors, the strength depended on species composition and was independent of conspecific load size. Different types of interactions (additive and synergistic) are hypothesized to underlie the diverse effects on M. guttatus reproductive success. • Our results suggest that an increase in the diversity of heterospecific donors will not always lead to a greater decrease in fitness because multispecies effects depend on the interacting species.
• 在自然群落中，植物既可以从同种植物也可以从异种种群中获得花粉。然而，关于种间花粉转移影响的研究主要集中在物种对之间的相互作用上。在柱头的异种种花粉（HP）粒之间存在着多种相互作用的可能性，这些相互作用可能会影响植物繁殖，无论是单独作用还是与同种花粉（CP）损失相结合，但这些相互作用尚未得到探索。 • 我们使用人工授粉来模拟越来越多的群落多样性和 CP 损失对 Mimulus guttatus 柱头的影响。我们使用一到三种异源供体的花粉混合物来确定物种组成和 CP 负荷大小如何影响种子产量，并描述导致受精失败的机制。 • 异源花粉沉积降低了 M. guttatus 的种子产量，而且这种影响随着异源供体数量的增加而增加，但强度取决于物种组成，与同种负荷大小无关。不同类型的相互作用（相加和协同）被假设为 M. guttatus 生殖成功的不同影响的基础。 • 我们的研究结果表明，异源供体多样性的增加并不总是会导致适应性降低，因为多物种效应取决于相互作用的物种。
