Stormwater biofilter systems can provide at-source pollutant removal and runoff reduction. However, vegetation in biofilters systems can be prone to drought stress, reducing plant health and survival in between rainfall events. Mycorrhizal colonization has been shown to improve nutrient removal in stormwater biofilter systems, but it is not yet known whether mycorrhizal colonization of biofilter plants can improve their water use or resistance to drought stress. We used a pot dry-down experiment to determine whether mycorrhizal colonization differs among six common biofilter plant species and whether it improves their water use or changes their drought resistance. We measured evapotranspiration (ET) during a well-watered (WW) phase before commencing a water-deficit (WD) phase, where pots were no longer watered. Predawn and midday water leaf water potentials were measured when plants had effectively ceased ET. Water use during the WW phase ranged between 4.6 and 5.9 mm day-1 and there was no significant difference in evapotranspiration between inoculated and control treatments. Cumulative water use during the WD phase was also unaffected by mycorrhizal colonization. Species with greater biomass ceased ET earlier than those with less biomass. While greater colonization was correlated with greater biomass, there was no significant difference in biomass between control and inoculated plants. These results suggest that mycorrhizal inoculation does not improve plant water use or drought resistance in biofilters. However, as all plants were drought avoiders, they are unlikely to experience drought stress regularly, unless the period between rainfall events is substantial.

中文翻译：

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生物过滤植物的菌根定植是否能提高它们的吸水率或抗旱性？


雨水生物过滤器系统可以在源头上去除污染物并减少径流。然而，生物过滤器系统中的植被容易受到干旱胁迫，从而降低植物健康和降雨事件之间的存活率。菌根定植已被证明可以改善雨水生物过滤系统中的营养物质去除，但目前尚不清楚生物过滤植物的菌根定植是否可以改善其水分利用或对干旱胁迫的抵抗力。我们使用花盆干燥实验来确定六种常见生物过滤植物物种的菌根定植是否不同，以及它是否改善了它们的水分利用或改变了它们的抗旱性。在开始缺水 （WD） 阶段之前，我们测量了浇水充足的 （WW） 阶段的蒸散 （ET），此时花盆不再浇水。当植物有效地停止 ET 时，测量黎明前和正午的水叶水势。WW 阶段的用水量在 4.6 至 5.9 mm day-1 之间，接种处理和对照处理之间的蒸发蒸腾没有显着差异。WD 阶段的累积用水量也不受菌根定植的影响。生物量较大的物种比生物量较少的物种更早停止 ET。虽然较大的定植与较大的生物量相关，但对照植物和接种植物之间的生物量没有显着差异。这些结果表明，菌根接种不会改善生物过滤器中的植物水分利用或抗旱性。然而，由于所有植物都是干旱回避者，除非降雨事件之间的间隔很长，否则它们不太可能经常经历干旱胁迫。