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.

The developmental stage has an influence on the overall responses of plants under biotic or abiotic stress conditions. However, there is a lack of data about the effects of ionizing radiation in plants at different developmental stages. We examined radiation sensitivity of Arabidopsis plants in terms of photosynthetic ability and oxidative stress resistance at two distinct vegetative and reproductive stages, which correspond to 23 and 43 d after seeding (DAS), respectively. When plants were exposed to γ rays at a dose rate 50 Gy h(-1) for 4 h, they were characterized as various common or differential cellular responses depending on the developmental stage. Radial expansion of leaves, inhibition of non-photochemical quenching, and production of •O(2)(-) and H(2)O(2) under methyl viologen-induced photooxidative stress were commonly more conspicuous in the irradiated leaves of both plants than in the respective control. In contrast, the 23 and 43-DAS plants were explicitly discriminated in growth, chloroplast number & ultrastructure, photosynthetic pigment content & activity, and protein damage after γ irradiation. Natural leaf senescence was thereby enhanced in the irradiated leaves of the 23-DAS plants, while it was reversely alleviated in those of the 43-DAS ones. These results suggest that photosynthetic machineries of Arabidopsis plants at the reproductive stage can be relatively tolerant to γ rays of 200 Gy.

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.