目的:环境中的非生物和生物成分都限制了植物的繁殖,但是他们如何在组合中相互作用却鲜为人知。了解这些相互作用尤其重要,因为非生物和生物环境成分对各种全球变化驱动因素的反应不同。在这里,我们旨在了解授粉(生物成分)对植物繁殖的影响是否取决于土壤水分(非生物成分),已知影响植物繁殖的两个因素随着全球变化而变化。
方法:我们对两种植物进行了花粉补充实验,飞燕草和飞燕草,在美国西部的亚高山草甸中,土壤湿度在四年中变化。在另一项为期一年的现场实验中,我们按因素将水添加与花粉补充交叉。我们测量了坐果的比例,每个水果的种子,和每株植物的种子,除了气孔导度,以确定植物生理学是否对浇水有反应。
结果:在为期四年的研究中,只有H.Fendleri的繁殖是花粉有限的,这与土壤湿度无关。实验添加水均显着增加了两种物种的土壤水分和气孔导度。花粉添加对繁殖的影响仅取决于对H.fendleri果实生产的浇水处理。在D.nuttallianum繁殖没有显著的影响花粉添加或水的添加,但它确实响应了土壤水分的年际变化。
结论:尽管我们发现了一些证据表明生物相互作用的效果取决于非生物条件,这只是一个物种繁殖的一个方面,这是一个意想不到的方向。我们的工作强调了环境中非生物和生物成分之间的相互作用,作为进一步研究的领域,以提高我们对植物繁殖如何响应全球变化的理解。
OBJECTIVE: Abiotic and biotic components of the environment both limit plant reproduction, but how they interact with one another in combination is less understood. Understanding these interactions is especially relevant because abiotic and biotic environmental components respond differently to various global change drivers. Here we aim to understand whether the effects of pollination (biotic component) on plant reproduction depend on soil moisture (abiotic component), two factors known to affect plant reproduction and that are changing with global change.
METHODS: We conducted pollen supplementation experiments for two plant species, Delphinium nuttallianum and Hydrophyllum fendleri, in subalpine meadows in the Western USA across four years that varied in soil moisture. In a separate one-year field experiment, we factorially crossed water addition with pollen supplementation. We measured proportion fruit set, seeds per fruit, and seeds per plant, in addition to stomatal conductance, to determine whether plant physiology responded to watering.
RESULTS: In the four-year study, only H. fendleri reproduction was pollen limited, and this occurred independently of soil moisture. Experimental water addition significantly increased soil moisture and stomatal conductance for both species. The effect of pollen addition on reproduction depended on the watering treatment only for H. fendleri fruit production. Reproduction in D. nuttallianum was not significantly affected by pollen addition or water addition, but it did respond to interannual variation in soil moisture.
CONCLUSIONS: Although we find some evidence for the effect of a biotic interaction depending on abiotic conditions, it was only for one aspect of reproduction in one species, and it was in an unexpected direction. Our work highlights interactions between the abiotic and biotic components of the environment as an area of further research for improving our understanding of how plant reproduction responds to global change.