Qianqian Sheng

Efficient cultivation is essential for the rose industry. Both substrate formulation and plant growth-promoting rhizobacteria (PGPR) application both critical, yet their synergistic effects remain limited. This study investigated the synergistic effects of Bacillus subtilis (Bs) and Priestia megaterium (Pm) combined with five substrate formulations on the growth physiology, photosynthetic characteristics, and soil properties of Rosa × hybrida ‘Ruby’. Two-way ANOVA revealed significant interactions between substrate and PGPR treatments for most growth and physiological indicators. Orthogonal experiments demonstrated that specific PGPR–substrate combinations significantly enhanced plant growth and photosynthetic performance of the studied cultivar, as well as soil quality. Principal component analysis and membership function analysis identified four substrate–PGPR combinations as optimal, with the T4 substrate (humus/perlite/vermiculite/coconut coir/peat/biochar = 5:1.5:1:1:1:0.5) showing the most pronounced effects. In this T4 substrate, PGPR inoculation significantly altered the rhizobacterial community structure. LEfSe analysis revealed 67 enriched microbial biomarkers—substantially more than single-strain treatments. The relative abundance of beneficial genera such as Acidibacter and Chryseotalea increased, and the combined bacterial treatment enhanced functional pathways associated with signal transduction, cell motility, and RNA processing. Compared to single-strain treatments, the combined bacterial application demonstrated superior regulatory effects on plant growth. The optimal combined treatments increased plant height by up to 42.7%, root activity by 103.0%, soluble protein content by 302.8%, and soil ammonium nitrogen by 168.8%. These findings demonstrated that tailored combinations of PGPR and cultivation substrates highlight the potential for optimizing rose cultivation and improving the rhizosphere microecological environment.

Carpinus betulus is an important ornamental landscape tree species with colorful foliage. It is widely used in landscaping due to its upright tree shape, significant seasonal changes, and good tolerance to pruning. Propagation methods for C. betulus include grafting, cutting, and seeding. However, the germination rate of seeding is low, and the rooting of cuttings is difficult; moreover, plant tissue culture techniques are complex, and the key technologies have not been disclosed. Grafting has therefore become the primary means of propagation. However, enabling the rapid reproduction of C. betulus through appropriate grafting methods and in appropriate environments remains an urgent issue to be addressed. In this study, Carpinus turczaninowii was used as a rootstock to graft C. betulus, and the effects of the grafting periods, technique, and environmental conditions on the survival rate of grafted C. betulus were discussed. The results showed that branch grafting (cleft graft and whip-and-tongue graft) performed in March to April and August to November resulted in the highest survival rates, whereas budding grafts (chip budding and patch budding) were more suitable in May and June. Increasing ambient humidity was a key measure for improving graft survival rates and germination rates. In terms of grafting survival rate, germination rate, and leaf growth, humidification and treatment with 60–70% light transmission had better results than treatment with natural humidity or 20–30% light transmission and full light treatment under humidification conditions. Under low-light conditions, increasing air humidity had a particularly pronounced effect on promoting the growth of grafted seedling branches. In the future, further research should be conducted on the molecular mechanism mediated by soil environment and temperature changes for the successful grafting of C. betulus, providing a theoretical basis for the propagation and cultivation of C. betulus.

Cultural ecosystem services (CESs) are the non-material benefits people derive from ecosystems and are important for human well-being. Most research has focused on individual CES supply–demand relationships, with little systematic study of the overall CES structure, interactions, and mechanisms in metropolitan areas. This study takes the Nanjing Metropolitan Area as a case study, integrating multi-source geospatial data and employing the MaxEnt model, self-organizing maps (SOMs), Spearman correlation analysis, and the Optimal Parameters-based Geographical Detector (OPGD). It analyzes supply–demand matching, trade-offs, synergies, and drivers for four CES categories: aesthetic (AE), recreational entertainment (RE), knowledge education (KE), and cultural diversity (CD). The main findings are as follows: (1) CES supply and demand are spatially zoned: the core area has surplus supply, secondary centers are balanced, and the periphery has both weak supply and demand. (2) Three supply–demand bundles have distinct synergy and trade-off patterns: Bundle 1 primarily exhibits strong synergy between AE and CD; Bundle 2 shows a weak trade-off relationship; and Bundle 3 forms a synergy centered on AE. (3) The explanatory power of driving factors exhibits pronounced spatial heterogeneity: Bundle 1 is dominated by non-quantifiable social factors; Bundle 2 features dual synergistic drivers of population and transportation; and Bundle 3 demonstrates synergistic effects driven by facilities and economic factors. Overall, this study contributes an integrated metropolitan-scale framework that connects CES supply–demand mismatch patterns with bundle typologies, interaction structures, and bundle-specific drivers. The results provide an operational basis for targeted planning and coordinated ecological–cultural governance in the Nanjing Metropolitan Area and offer a transferable reference for other metropolitan regions.

Urban green spaces, as crucial components, can effectively mitigate atmospheric pollutants such as NO₂. However, the heterogeneous driving forces and the underlying quantitative mechanisms of different vegetation community structures in response to NO₂ exposure remain insufficiently explored. This study utilized a laboratory-based artificial fumigation method to examine the NO₂ mitigation benefits and response mechanisms of three representative vegetation structures (tree–shrub–grass, tree-shrub, and tree-grass) as well as their monoculture communities under NO₂ stress. The objective was to elucidate the variations in NO₂ reduction capacity and the adaptive mechanisms associated with different vegetation structures. The results demonstrated that, under NO₂ exposure, the NO₂ reduction rate of the tree–shrub–grass mixed community was 56.15 mg·h⁻¹. NO₂ stress inhibited leaf morphogenesis and plant growth. However, the tree–shrub–herbaceous community enhanced its NO₂ tolerance by reallocating photosynthetic products and increasing epidermal thickness, stomatal density, and the compactness of tissue structure, thereby strengthening its mechanical barrier function. The NO₂ reduction rate was positively correlated with parameters such as net photosynthetic rate, stomatal density, leaf width, transpiration rate, and stomatal conductance, but negatively correlated with fluorescence and the leaf length-to-width ratio. A comprehensive evaluation based on fuzzy membership functions ranked the NO₂ mitigation and tolerance capacities of plant communities as follows: the tree–shrub–herbaceous community exhibited the strongest capacity for NO₂ reduction and stress tolerance. Thus, in NO₂-polluted areas, priority should be given to establishing tree–shrub–grass composite vegetation structures, whose multidimensional resistance mechanisms provide both a theoretical foundation and a technical pathway for the ecological restoration of urban green spaces.

Port green spaces are essential protective barriers, enhancing safety and environmental resilience in high-activity port regions. Given the intensity of human activities in these areas, understanding the factors influencing the carbon sequestration capacity and ecological benefits of port green spaces is crucial for developing sustainable green ports. This study integrated field investigations and remote sensing data to estimate carbon density and carbon sequestration capacity in the Dongjiakou Port area, examining their relationship with port green space planning. The results indicated that carbon density in green spaces showed a significant negative correlation with the number of lanes in adjacent roads, where an increase in lane numbers corresponded to lower carbon density. Additionally, carbon density decreased significantly with increasing distance from the shipping center. In contrast, a significant positive correlation was observed between carbon density and distance from large water bodies, indicating that green spaces closer to large water bodies exhibited smaller carbon density. Infrastructure development in Dongjiakou substantially negatively impacted vegetation carbon sequestration capacity, with effects not reversible in the short term. However, green space enhancement efforts provided additional ecological benefits, leading to a 50.9 ha increase in green space area. When assessing carbon density in urbanizing areas, geographical influences should be prioritized. Furthermore, the long-term environmental impacts of urban expansion must be considered at the early planning stages, ensuring the implementation of proactive protective measures to mitigate potential ecological disruptions.