Abstract Vegetated roofs, often called “green roofs”, are popular and necessary in urban greening in densely populated areas. Well-functioning vegetated roofs can provide various ecosystem services to urban residents (e.g., stormwater management, air pollution mitigation, and aesthetic value). Plants essentially determine the actualization of the ecosystem services, thus finding effective ways to establish and maintain the roof plants is important. While greenhouse experiments can be better controlled than field experiments, it is critical to test whether results gained in the greenhouse hold in actual roof conditions. Therefore, we investigated the effects of microbial inoculant, plant species, planting method, and their interactions on plant growth and the beneficial microbes in the roof substrate at the initial establishment of vegetated roofs. The selected plants (i.e., Antennaria dioica, Campanula rotundifolia, Fragaria vesca, Geranium sanguineum, Lotus corniculatus, Thymus serpyllum, Trifolium repens, and Viola tricolor) were established using pre-grown vegetation mats, plug plants, and seeds, each with and without the co-inoculation with Rhizophagus irregularis and Bacillus amyloliquefaciens, two plant growth-promoting microbial species. Eventually, only F. vesca, T. serpyllum, T. repens, and V. tricolor were found successfully settled in either of the three planting methods. Dry aboveground plant biomass was measured to assess the effects of co-inoculation on plant growth. R. irregularis colonization level and B. amyloliquefaciens bacterial density were detected from root and substrate samples, respectively. The results indicated that co-inoculation with R. irregularis and B. amyloliquefaciens successfully colonized target plant species and significantly increased the initial growth of the vegetated roof plants by 18–292%. Additionally, the abundance of R. irregularis was affected by plant species (F. vesca > T. serpyllum > T. repens) and planting methods (seed > plug > mat), while the bacterial density of B. amyloliquefaciens was higher in T. repens roots than the other plant species, and was not affected by planning methods. The results suggest that co-inoculating R. irregularis and B. amyloliquefaciens at the installation phase of vegetated roofs could improve microbial settlement and colonization in the substrate, and consequently achieve synergistic effect on plant growth. The study also provides basis and reference for future vegetated roofs research.

中文翻译：

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案例研究：种植方法和有益基质微生物对芬兰屋顶植物生长的影响

摘要 植被屋顶，常被称为“绿色屋顶”，在人口稠密地区的城市绿化中是流行和必要的。功能良好的植被屋顶可以为城市居民提供各种生态系统服务（例如，雨水管理、减轻空气污染和审美价值）。植物本质上决定了生态系统服务的实现，因此找到建立和维护屋顶植物的有效方法很重要。虽然温室试验可以比田间试验更好地控制，但测试温室中获得的结果是否在实际屋顶条件下保持是至关重要的。因此，我们研究了微生物接种剂、植物种类、种植方法及其对植物生长的影响以及植被屋顶初始建立时屋顶基质中有益微生物的影响。选定的植物（即，Antennaria dioica、Campanula rotundifolia、Fragaria vesca、Geranium sanguineum、Lotus Corniculatus、Thymus serpyllum、Trifolium repens 和 Viola tricolor）是使用预先种植的植被垫、栓塞植物和种子建立的，每种植物都有或没有与不规则根瘤菌和解淀粉芽孢杆菌（两种促进植物生长的微生物物种）共同接种。最终，只有 F. vesca、T. serpyllum、T. repens 和 V. tricolor 被发现在三种种植方法中的任何一种中成功定居。测量干燥的地上植物生物量以评估共同接种对植物生长的影响。分别从根和基质样品中检测到不规则 R. 定植水平和解淀粉芽孢杆菌细菌密度。结果表明，与 R.informiser 和 B. amyloliquefaciens 成功地定殖目标植物物种，并显着增加了植被屋顶植物的初始生长 18-292%。此外，R.informalis 的丰度受植物种类（F. vesca > T. serpyllum > T. repens）和种植方法（种子 > 栓塞 > 垫子）的影响，而 B. amyloliquefaciens 的细菌密度在 T.比其他植物物种更重，并且不受规划方法的影响。结果表明，在植被屋顶的安装阶段共接种不规则红曲霉和解淀粉芽孢杆菌可以改善基质中的微生物沉降和定植，从而对植物生长产生协同效应。该研究也为未来植被屋顶的研究提供了依据和参考。