## 4 Conclusions  
This study conducted an assessment of the suitability of using PC for vegetation growth from the perspective of plant physiology. The growth and physical indexes of the three plant species were analysed and monitored. Mechanical property tests, vegetation tests, and PCAs were conducted on samples in the different concretes to determine the differences in plant growth among PC (5-10 and 15-20 mm) and near-natural growing conditions. Based on the tests above, the following conclusions were obtained:  
Based on the results of plant growth, correlation analysis, physiological indexes, PCA, and soil composition tests, the PC concrete matrix was not as effective as the natural growing environment, regardless of the diameter of the aggregate particles. The materials introduced by concrete may adversely affect plant growth. Plants generally suffered more abiotic stress in the SC treatments. In the interspecific comparison tests, _C. dactylon_ and _A. stolonifera_ suffered various degrees of damage in PC treatments, as indicated by their lower detected MDA and SP concentrations. However, the cell membranes of roots were not significantly damaged, and the plants were able to grow normally. Because of the low permeability of the SC containers, the root systems suffered from hypoxia, which had a certain degree of influence on the growth of roots. Therefore, in the performance evaluation of the plant morphology of _A. stolonifera_, the LC treatment was more suitable than the SC treatment. The MDA and REC levels in _S. argenteostriatus_ in the SC treatment group were significantly higher than those in the plants in the NC and LC treatment groups, indicating that _S. argenteostriatus_ was under greater stress. This occurred because for _S. argenteostriatus_, in moist and acidic soils, its well-developed underground stem and root systems develop a network structure and have a high water and soil conservation capacity [47]. For the matrix with a small pore size, such as that of the SC treatment group, its drainage capacity is not as high as that of the matrix with a large pore size (LC and NC treatment groups), which causes the root system to be in a constant state of water flooding and simultaneously leaches alkaline ions from the concrete, resulting in greater stress. For the LC treatment group, the drainage capacity was higher than that in the SC treatment group, and the water flooding effect on _S. argenteostriatus_ was reduced. Most plants are more likely to grow well in concrete types with higher porosity and larger pore size than in SC. This phenomenon is consistent with the results of previous studies [48]. PCA allowed us to determine that the main factors influencing the growth of the other SC groups in addition to the control group were SP, REC, MDA and alkalinity; SP, REC, and MDA were the main influencing factors in the LC group. These results indicated that the plants were under stress during their growth in the PC groups. Plants planted on PC or in pores require more careful care, such as the usage of fertilizer. PCA and correlation analysis showed that Pro could not objectively or accurately characterize the vegetative growth process of plants in this experiment. Regarding the limitations of this research, future studies should be conducted in terms of long-term practical applications to ensure the ecological functions, landscape effects and sustainable development of slope protection. In addition, more PC specimens of different particle sizes need to be tested. According to the characteristics of PC, the most suitable slope protection plants can be selected, and added plant species should be studied, in addition to herbs, such as shrubs and even small trees. Physiological indicators under different conditions could be used to reach more accurate conclusions. Overall, planting concrete has good engineering performance, and it can provide help for infrastructure construction to promote connectivity between ecosystems.