Nature-based solutions (NBS), exemplified by external green walls, play a crucial role in bolstering the sustainability of cities by mitigating heat islands and moderating temperatures. Nevertheless, owing to the lavish consumption of urban water in green walls, the adoption of recycled water for irrigation within these infrastructures emerges as a widely employed strategy. We conducted an investigation on the accumulator ornamental species Aptenia cordifolia and Carpobrotus edulis, exploring the effects of treatments involving recycled water and the application of PGPR. This research consisted of two separate experiments, each focused on a different plant species. The experiments were structured as split-plot layout based on a randomized complete block design with three replications from March to December 2022 on an external green wall. The main factor was recycled waters with three levels (gray water, wastewater from the Kashfroud region of Mashhad, and urban water (control)). The sub-factor included different bacterial strains at four levels, composed of various bacterial combinations such as B1, B2, B3, and B0 as the control level without bacterial application. The results indicated that the highest number of flowers per individual plant (6.58) and in the unit (9.33), flower diameter (8.98 mm), leaf surface area (66.26 cm3), and fresh and dry biomass (322.40 g per plant and 35.93 g per plant, respectively) were recorded in A. cordifolia with Mix B3 and irrigation with wastewater. Meanwhile, in the Carpobrotus, the highest leaf surface area (70.31 cm3) was associated with Mix B3 and irrigation with gray water. The Carpobrotus, with Mix B1, had the highest fresh biomass (393.71 g per plant), and with Mix B3, it exhibited the highest dry biomass (35.93 g per plant) when irrigated with wastewater. According to the results in A. cordifolia and C. edulis, Mix B3 and irrigation with wastewater increased WUE by approximately 40 % in the spring and autumn seasons. It is noteworthy that during the summer season, WUE exceeded 50 % based on the growth index. The results of this study recommend the combination of the substrate with Mix B3 and irrigation with wastewater, along with using A. cordifolia instead of other unstable plants on the external green wall in dry and semi-dry climates.

中文翻译：

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绿化外墙条件下循环水灌溉下植物促生长菌对 Aptenia cordifolia 和 Carpobrotus edulis 功能和热力学特性的影响


以外部绿化墙为代表的基于自然的解决方案 （NBS） 通过缓解热岛效应和缓和温度，在促进城市可持续发展方面发挥着至关重要的作用。然而，由于城市用水在绿化墙中大量消耗，在这些基础设施中采用循环水进行灌溉成为一种广泛采用的策略。我们对蓄能观赏物种 Aptenia cordifolia 和 Carpobrotus edulis 进行了调查，探讨了涉及循环水和 PGPR 应用的处理效果。这项研究包括两个独立的实验，每个实验都侧重于不同的植物物种。实验结构为基于随机完整区组设计的拆分小区布局，从 2022 年 3 月至 12 月在外部绿化墙上进行了三次重复。主要因素是三个级别的循环水（灰水、马什哈德 Kashfroud 地区的废水和城市水（对照））。亚因子包括 4 个水平的不同细菌菌株，由 B1 、 B2 、 B3 和 B0 等多种细菌组合组成，作为无细菌施用的对照水平。结果表明，单株花数 （6.58） 和单位 （9.33）、花径 （8.98 mm）、叶表面积 （66.26 cm3） 以及新鲜和干燥生物量 （分别为每株 322.40 g 和每株 35.93 g） 中，濑桐椿在混合 B3 和废水灌溉下记录了最高的花数。同时，在 Carpobrotus 中，最高的叶表面积 （70.31 cm3） 与 Mix B3 和灰水灌溉有关。与混合物 B1 一起，Carpobrotus 的新鲜生物量最高（每株植物 393.71 克），而与混合物 B3 一起，它的干生物量最高（35.每株 93 克）。根据 A. cordifolia 和 C. edulis 的结果，混合 B3 和废水灌溉使春季和秋季的 WUE 增加了约 40%。值得注意的是，在夏季，根据增长指数，WUE 超过 50%。这项研究的结果建议将基质与 Mix B3 和废水灌溉相结合，并在干燥和半干燥气候下在外绿墙上使用 A. cordifolia 而不是其他不稳定的植物。