Plant communities in urban wetland parks (UWP) have significant eco-healthcare benefits in terms of regulating the climate and improving the human living environment. However, factors influencing the regulation of eco-healthcare benefits are unclear. Taking Huaxi Ten Mile Beach National Urban Wetland Park as an example, the urban wetland park comprehensive healthcare index (UPCHI) was constructed based on an outdoor survey and indoor analysis to evaluate the UWP’s eco-healthcare benefits. Pathway analysis was used to investigate how climatic, geographic, and plant factors interact to affect the UPCHI. The results show that, over the whole year, tree–shrub–herb showed the best performance in terms of reducing PM_2.5, PM₁₀, and noise, as well as raising negative air ion concentrations; however, human comfort performed the worst. The UPCHI was generally beyond level Ⅲ (0.49–0.58) in the spring and summer, indicating that there are eco-healthcare benefits. Overall, the deciduous tree–shrub–herb community had the highest annual mean UPCHI, and more than half of the plant communities’ eco-healthcare benefits were class Ⅱ, which is very beneficial for eco-healthcare. The main direct factors on UPCHI were illumination intensity (0.68) and tree height (0.90), while canopy height (0.64–0.59) and tree crown radius/canopy height (0.72–0.14) directly or indirectly influenced UPCHI. The distance from the edge of the mountain (−0.39–−0.322) had a direct negative, but minor, effect on UPCHI. This study will assist residents with selecting suitable times and places for wetland recreation and healthcare activities, and it offers a valuable reference for the future planning and design of UWP plant communities.

The symbiosis between ectomycorrhizal (ECM) fungal species and the root system of Pinus massoniana is important for its growth. However, the characteristics of ECM fungal communities and their relationships with extracellular enzyme activities and nutrients in the rhizosphere soil of different P. massoniana genotypes have not been well characterized. In this study, P. massoniana families (groups of offspring from different parents) with different levels of growth were selected for investigating ECM fungal communities, soil nutrients, extracellular enzyme activity, and leaf nutrient concentrations to explore the relationships between P. massoniana and the composition of the ECM fungal community. The high-growth (HG) family of P. massoniana had more different ECM fungal communities than the medium-growth (MG) and low-growth (LG) families; each family had a unique and dominant genera (HG: Amphinema and Pseudoclathrosphaerina; MG: Russula and Auricularia; and LG: Russula and Amanita). Amphinema was the main contributor to the differences among the three families (contribution: HG-MG 0.225 and HG-LG 0.17) and had rich extramatrical mycelium, which favored the growth of the HG family and positively affected the accumulation of soil organic carbon. Structural equation modelling showed that the dominant genera in the HG family had significant positive effects on the activity of three extracellular enzymes (BG, NAG, and AP) (weak to moderate positive effects of Amphinema on BG, NAG, and AP and moderate positive effects of Pseudoclathrosphaerina on BG, NAG, and AP), which might have contributed to the differences in extracellular enzyme activities among the families with different growth levels. Redundancy analysis indicated that P. massoniana growth traits (tree height, diameter at breast height, and timber volume), soil total nitrogen, and the N/P ratio significantly influenced ECM fungal communities. The study revealed the characteristics of ECM fungal communities, soil extracellular enzyme activity, and nutrient features of P. massoniana with different growth levels, which help improve our understanding of the relationship between P. massoniana genotype and ECM fungal communities.

Cold acclimation before winter has been shown to enhance the cold tolerance of evergreen conifers, including Pinus massoniana Lamb., a characteristic heteroblastic foliage tree in the conifer. In the initial growing season of P. massoniana, both primary needle seedlings (PNSs) and secondary needle seedlings (SNSs) are generated. While previous research has highlighted differences in the morphological structure and photosynthetic physiological functions of primary and secondary needles, their response to cold acclimation remains poorly understood. This study aimed to investigate the changes in morpho-anatomical structure, starch grain accumulation, and lignin deposition in the roots, stems, and leaves of PNSs and SNSs during cold acclimation using solid potassium iodide and hydrochloric acid phloroglucinol double-staining techniques. The results revealed that, during cold acclimation, the leaves and stems of PNSs exhibited sensitivity to low-temperature stress, resulting in noticeable shrinkage and fracture of mesophyll and cortical parenchyma cells. Furthermore, the early stages of cold acclimation promoted the accumulation of starch grains and lignin in the seedling tissues. In contrast to PNSs, the leaves and stems of SNSs exhibited a shorter cold acclimation period, attributed to the hydrolysis of starch grains in the epidermal cell walls and the transformation of xylem lignin, which supports cell structure stability and enhances cold resistance. In conclusion, these findings suggest that SNSs displayed a superior cold resistance potential compared to PNSs following cold acclimation, providing a significant theoretical basis for the further screening of cold-tolerant germplasm resources of P. massoniana and the analysis of cold resistance traits in heteroblastic foliage.

Pinus massoniana Lamb. is an evergreen conifer; however, some current-year seedlings exhibit “winter reddening” at the onset of winter. The biological significance of this reddening is unclear. We examine the physiological responses of needles during the reddening process and explore the relationships between physiological traits and seeding cold resistance. Based on needle color, we recognize non-reddened, partially reddened, and fully reddened needle stages. As reddening progresses, chlorophyll fluorescence parameters (maximum light energy conversion efficiency of photosystem II (PSII) photochemistry, PSII potential activity, effective photosynthetic quantum yield, non-photochemical and photochemical quenching coefficients, and actual quantum yield of PSII photochemistry) decrease, reducing photosynthetic efficiency. Concurrently, the proportion of regulated energy dissipation in quantum yield of PSII decreases, and that of PSII non-regulated energy dissipation increases. Antioxidant enzyme activities (catalase and peroxidase) and osmoregulatory substances (soluble sugars and proteins and proline) increase, and malondialdehyde levels and relative cell damage at 4 °C and −10 °C gradually increase. Although P. massoniana seedlings adapt to low-temperature environments as their needles redden by increasing antioxidant enzyme activities and osmoregulatory substances and by adjusting photosynthetic efficiency and light energy distribution, cell membrane damage persists. Cold resistance in P. massoniana seedlings is not fully established during winter reddening.