Research on plant species and substrate materials for vertical greenery systems under water-stress condition

Vertical greenery system (VGS) is gaining increasing attention owing to their various ecosystem services; however, their potential remains underutilised in urban areas. The impact of certain plant species and substrate options on the performance of VGS requires further research. Under flooding conditions, the production and release of reactive oxygen species in plants fail to maintain a balanced state, whereas, under drought conditions, plants may be exposed to severe or even lethal stress levels. Therefore, in this study, six native species were selected and evaluated in the laboratory for their photosynthetic and physiological characteristics under drought and flooding stress to identify stress-tolerant species for further application in VGS. Nine substrate compositions (T1–T9) were tested using different proportions of renewable materials (green waste, corn straw, and biogas residue). Their physicochemical properties, nutritional capacities, and feasibility as growing media for VGS were assessed by comparison with previously reported substrates. The findings revealed that Buxus sinica Cheng performed best under water stress conditions and ranked highest in the overall evaluation index; thus, it is an ideal plant for VGS application. The T7 composite medium showed the best performance in facilitating plant growth and development, including an increase in plant biomass and improvement in photosynthetic and physiological indicators. This research can act as a reference and practical guide for the construction of VGS.