Abstract Pollinators provide crucial urban ecosystem services. Introducing nectar-producing species on green roofs is one method to support pollinator populations. However, novel cultivation methods may be required to improve plant health with minimal irrigation on extensive green roofs, which are severely restricted in soil thickness. Although companion planting with CAM plants such as Sedum has been reported to improve the performance of neighboring plants, the growth form of the beneficiary species seems important in determining the effectiveness of the technique. In this study, eleven species of nectar-producing plants were classified into two growth forms: carpet species (Phyla canescens, Trifolium repens, Thymus serpyllum and Thymus longicaulis), non-carpet species (Calamintha nepeta, Lavandula officinalis, Lavandula stoechas, Melissa officinalis, Mimosa pudica, Rosmarinus officinalis ‘Erectus’, Rosmarinus officinalis ‘Prostratus’), and were planted together with Sedum album in a greenhouse or on a rooftop space. There were no net positive effects in the impacts of companion planting with S. album on plant biomass both in carpet and non-carpet species. However, companion planting with S. album had net positive effects on leaf health in L. stoechas, M. officinalis, M. pudica, and R. officinalis ‘Prostratus’, classified as non-carpet species. In contrast, there were no positive effects on carpet species, planted together with S. album. These results suggest that complementary growth forms could be one of the factors to determine effective planting combinations to improve plant health conditions on extensive green roofs. Additionally, the increase in soil water content by suppressing evapotranspiration when water is limiting can be effective in improving leaf health conditions of neighbors in companion planting with S. album. While past studies have shown positive benefits of companion planting with CAM species, this experiment suggests the possibility that not all growth forms may benefit from facilitation by Sedum.

中文翻译：

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生长形态对大面积绿化屋顶景天与产花蜜植物伴生影响的影响

摘要 传粉媒介提供重要的城市生态系统服务。在绿色屋顶上引入产花蜜物种是支持传粉媒介种群的一种方法。然而，可能需要新的栽培方法来改善植物健康，同时在土壤厚度受到严重限制的大面积绿色屋顶上进行最少的灌溉。尽管据报道与景天等 CAM 植物一起种植可以提高邻近植物的性能，但受益物种的生长形式似乎对确定该技术的有效性很重要。在这项研究中，11 种产蜜植物被分为两种生长形式：地毯种（Phyla canescens、Trifolium repens、Thymus serpyllum 和 Thymus longicaulis）、非地毯种（Calamintha nepeta、Lavandula officinalis、Lavandula stoechas、Melissa officinalis、Mimosa pudica、Rosmarinus officinalis 'Erectus'、Rosmarinus officinalis 'Prostratus')，并与景天一起种植在温室或屋顶空间。在地毯和非地毯物种中，伴生植物 S.album 对植物生物量的影响没有净正面影响。然而，在被归类为非地毯物种的 L. stoechas、M. officinalis、M. pudica 和 R. officinalis 'Prostratus' 中，与 S.album 一起种植对叶子健康具有净正面影响。相比之下，对与 S.album 一起种植的地毯品种没有积极影响。这些结果表明，互补的生长形式可能是确定有效种植组合以改善大面积绿色屋顶植物健康状况的因素之一。此外，在水分有限的情况下通过抑制蒸发蒸腾来增加土壤含水量可以有效改善邻居与 S.album 同伴种植的叶片健康状况。虽然过去的研究显示了与 CAM 物种一起种植的积极好处，但该实验表明并非所有生长形式都可能受益于景天的促进作用。