High concentration of particulate matter (PM) threatens public health and the environment. Increasing traffic in the city is one of the main factors for increased PM in the air. Urban green spaces play an important role in reducing PM. In this study, the leaf surface and in-wax PM (sPM and wPM) accumulation were compared for 11 plant species widely used for landscaping in South Korea. In addition, biochemical characteristics of leaves (ascorbic acid chlorophyll content, leaf pH, and relative water content) were analyzed to determine air pollution tolerance. Plant species suitable for air quality improvement were selected based on their air pollution tolerance index (APTI) and anticipated performance index (API). Results showed a significant difference according to the accumulation of sPM and wPM and the plant species. PM accumulation and APTI showed a positive correlation. Pinus strobus showed the highest PM accumulation and APTI values, while Cercis chinensis showed the lowest. In 11 plants, API was divided into five groups. Pinus densiflora was classified as the best group, while Cornus officinalis and Ligustrum obtusifolium were classified as not recommended.

Particulate matter (PM) is the most dangerous form of air pollution and is known to cause severe health problems to humans. Plants as biological filters can reduce PM in urban areas by accumulating PM on the surface and epicuticular wax of leaves. The present study determined the amount of PM (large PM (10–100 µm) and coarse PM (2.5–10 µm)) collected on 10 plant species from two sites (urban forest and roadside) of Cheongju City, South Korea. Selected leaf traits (chlorophyll a (Chl a), chlorophyll b (Chl b), total chlorophyll (TChl), carotenoid, relative leaf water content (RWC), specific leaf area (SLA), and pH of these plant species at the two sites were concurrently determined to find about the correlation between the leaf straits and PM accumulation on leaf. Study results showed that the amount of accumulated large PM (10–100 µm) and coarse PM (2.5–10 µm) were different depending on the plant species and the collection site. Plants from the roadside tended to have higher amounts of PM accumulation as compared to the same plant species from the urban forest. In addition, the amount of PM accumulated on the leaf surface was higher than that of the epicuticular wax. PM accumulation on the leaf surface was positively correlated with the amount of PM accumulated on the epicuticular wax. Among the 10 plant species selected, P. strobus, P. densiflora, M. denudata, and S. vulgaris were the most effective plant for PM accumulation, while M. glyptostroboides was the least effective plant ones. Chl a, Chl b, TChl, and carotenoid contents were higher in plants collected along the roadside than in those collected from the urban forest, whereas RWC was higher in plants from the urban forest. No distinct tendency was noted regarding the pH. Coarse PM (2.5–10 µm) was negatively correlated with leaf traits of plants along the roadside. The tolerance of plants to pollution might be due to an increase in chlorophyll content. Features of the leaf were also essential in increasing PM accumulation on the leaf surface.

Particulate matter (PM), an extremely serious type of air pollution, leads to numerous human diseases. Mitigating PM in the urban city, where resident density has been increasing, has been a major challenge. The increase in residents leads to increasing traffic, the primary source of PM in urban areas. Plants play an important role in reducing PM and maintaining an ecological balance. For some Asian countries, such as Korea, with differing seasons and environmental conditions, PM accumulation and plant survival are greatly impacted by environmental conditions. In this study, we analyzed the amount of PM accumulation on the leaf surfaces and wax layers of 24 plant species during four seasons (spring, summer, autumn, and winter) to determine the PM accumulation in plants under different environmental conditions. The leaf traits of plant chlorophyll a (Chl a), chlorophyll b (Chl b), total chlorophyll (TChl), relative water content (RWC), leaf extract pH (pH), and leaf specific area (SLA) were analyzed to determine the influence of PM on plants and the relationship between PM and leaf traits. In this study, we found that the amount of PM accumulation differed among plants and seasons. Among the 24 plant species, plants Pinus strobus, P. parviflora, P. densiflora, Euonymus japonicus, and Acer palmatum were most adept at PM accumulation. Leaf structure, environmental conditions, such as PM concentration, and rainfall may be the main factors that impact the ability of plant leaves to accumulate PM. The plant leaf traits differed among the four seasons. PM accumulation on the leaf was negatively correlated with SLA (in all four seasons) and pH (in spring, summer, and autumn). PM was negatively correlated with Chl a, Chl b, and TChl in summer.

Background and objective Particulate matter (PM) is the most dangerous form of air pollution, and causes many diseases. Plants act as bio-filters to help reduce PM in the atmosphere. PM also influences the growth of plants, so selecting suitable plant species for specific environmental conditions is very important. The air pollution tolerance index (APTI) was used to determine the tolerance level of each plant species to air pollution. The purpose of this study was to determine the tolerance to air pollution of various plant species in order to identify plant species that can be grown in polluted environments; this was achieved by evaluating the APTI of plants. This study analyzed the biochemical parameters of 12 plant species at two sites with different air pollution levels (urban forest and roadside) to assess and compare the APTI of plant species. Methods The healthy leaves of 12 plant species (6 broad leaves and 6 needle leaves) that are commonly used in landscapes in Korea were chosen for this study. The same plant species were collected from two sites with different pollution levels and were analyzed immediately; one site was an urban forest (Chungcheongbuk-do Forest Environment Research Institute) with an area of 25 ha and featuring high vegetation coverage, while the other was at a high-traffic roadside next to a crossroads near the Cheongju Express Bus Terminal. We used the leaf samples to analyze four biochemical parameters of each plant: leaf extract pH (pH), relative leaf water content (RWC), total chlorophyll (TChl), and ascorbic acid. Finally, based on these values, APTI values were calculated. Results The APTI values were different between all 12 plant species at both sites with different levels of pollution. APTI had a significant correlation with the biochemical parameters of plants. Plants in the urban forest and at the roadside showed APTI values ranging from 6.89–9.37 and 7.57–9.94, respectively. The APTI of the roadside plant species tended to be higher than that of the plants from the urban forest. Among 12 plant species, Acer palmatum, Acer buergerianum, and Pinus densiflora had high APTI values. These plant species can serve as biofilters in environments with high air pollution. Conclusion The APTI of the 12 plant species in this study can aid in the selection of suitable plant species from environments with different levels of air pollution. The high APTI of some roadside plant species may show their tolerance under environmental pollution-related stress, or demonstrate their adaptability to the polluted environment. In the future, we need to examine more plant species under various environmental conditions to understand their tolerance levels to air pollution and to correlate plants with air pollution. Further, more studies on other air pollutants that can influence plant growth, such as SO2 and NOx, should be conducted.

Background and objective This study was conducted to establish a stable seedling production system for Veronica pusanensis Y.N. Lee, a plant that is endemic to the Korean Peninsula and is a critically endangered species, distributed along the coast of Busan, Korea. Methods In order to investigate the plug cell size (72, 128, 200 cells), soil type (commercial substrate, and mixed substrates with peat moss and perlite at ratios of 1:1, 3:1, and 4:1), and fertilizer concentration (Peters 0, 500, 1,000, and 2,000 mg·L−1) conditions, the plug tray was filled with soil and seeds were sown. The sown trays were placed in the growth chamber (25°C, 70% RH, PPFD 100 μmol·m−2·s−1) for three repetitions per treatment. Results There was no difference in the growth of seedlings according to plug cell size. Therefore, it appears to be economically superior to produce seedlings in a 200-cell plug tray. In soil type, the seedling growth increased as the ratio of peat increased, but leaf chlorosis occurred from the 7th week after sowing. Examining the growth of seedlings based on fertilizer concentration, the greatest increase in growth was found to have occurred in the 1,000 mg·L−1 treatment. Conclusion Therefore, for the production of V. pusanesis seedlings, it was noted that when mixed soil with peatmoss and perlite at a ratio of 4:1 is filled in 200-cell plug trays, and the seedlings are fertilized with Peters 1,000 mg·L−1 once a week, growth will increase the most, demonstrating excellent cost-effectiveness. However, to mass-produce high-quality seedlings in a short period, it will be necessary to use a plug tray smaller than 200 cells or to conduct various fertilization composition studies.

The objective of this study was to analyze the effects of calcium chloride (CaCl₂) used as a de-icing agent on growth and physiological responses of three ground cover plants, Hosta longipes, Iris ensata, and Iris pseudacorus. CaCl₂ concentration was set to be 0 mM (control), 9 mM (0.1%), 18 mM (0.2%), and 54 mM (0.6%). After treatment with CaCl₂ for 3 months, plant heights, fresh weights of shoots and roots, photosynthetic rates, chlorophyll fluorescence, chlorophyll content (SPAD), and leaf water potential were measured. After Hosta longipes was treated with CaCl₂ for 60 days, physiological damage began to occur in all treatment groups except for the control group. Those treated with 54 mM CaCl₂ completely withered. At 90 days after treatment (DAT), there were significant differences for all measured parameters for Hosta longipes compared to the control (p < 0.001). The higher the treatment concentration, the lower the photosynthetic rate, the SPAD, and the leaf water potential. There was no significant difference in plant height in Iris ensata after 60 DAT (p > 0.05), but in other physiological responses, there was a significant difference by concentration (p < 0.001). Iris ensata had a visually healthier state at 90 DAT, showing the smallest reduction in photosynthetic rate at 60 DAT and 90 DAT. Its SPAD value was increased more at 90 DAT than at 60 DAT, indicating its higher resistance to CaCl₂. Iris pseudacorus showed similar results as Iris ensata. Over time, the 54 mM treatment resulted in significant damage. Among these three plants, Iris ensata showed the highest tolerance to CaCl₂. Therefore, they are considered to be highly beneficial ground cover plants for green infrastructure in urban areas with high CaCl₂ concentrations.