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[Display omitted] Apparently, plant leaf surface particulate matter (PM) can be effectively removed by rainfall, leaving space on the leaf surface to adsorb and retain PM again. At present, most of the relevant studies adopt the method of artificial rainfall simulation to quantify rainfall characteristics in terms of rainfall intensity, and mostly focus on one category of plants. Studies of rainfall intensity on different categories of plants are lacking. Therefore, in this study, common urban greenery plants were classified into four categories, namely, trees, shrubs, herbs, and aquatic plants. Artificial rainfall was used and three different gradients of rainfall intensity, 30 mm/h, 45 mm/h and 60 mm/h, were set. The mass of per unit leaf area PM removal was calculated using the elution weighing method and the filter membrane method was used to classify the PM into three particle sizes: coarse (10–100-μm), fine (3–10-μm) and ultrafine (0.4–3-μm). It was devoted to investigating the differences in the effect of rainfall intensity on the removal of PM from the leaf surfaces of different categories of common urban greenery. The results showed that the removal of coarse particles by rainfall was the highest under different rainfall intensities. At the same time, the removal effects of rainfall on leaf surface PM of herbs were the highest under different rainfall intensity, while that of trees was the lowest. Among the same category of plants, Salix matsudana had better particle retention capacity among trees, Buxus sinica among shrubs, Poa pratensis among herbs, and Acorus calamus among aquatic plants. In addition, all tested plants had the highest mass of PM removed from leaf surface units at high rainfall intensity (60 mm/h). However, at a higher rainfall intensity (45 mm/h), the mass of PM on plant unit leaf surface removed was lower than the minimum rainfall intensity (30 mm/h). The results of the above study can provide a basis and theoretical support for the selection of species for urban green space restoration, as well as a reference for the establishment of urban cleaning systems from the perspective of the relationship between rainfall intensity and PM on plant leaf surfaces. [ABSTRACT FROM AUTHOR]

• Decomposition rate and effects were measured in field and laboratory experiments. • Measured soil properties and PLFAs for decomposition at different salinities and inundation environments. • Decomposition rate was correlated with water quality and fungal microbe content. • Leaf litter may control carbon cycling and energy flow in estuary ecosystems. • Artificially elevating wetland nutrient content may mitigate negative human impact. Decomposition of halophyte litter may considerably influence carbon cycling and energy flow in estuarine ecosystems. We examined water quality parameters, soil properties, and soil phospholipid fatty acid (PLFA) contents from the Yellow River Estuary, China, to investigate Phragmites australis and Suaeda glauca litter decomposition dynamics. Surface soils (0–10 cm) under three different salinity conditions were collected from six plots. Results showed that the litter decomposition rate of S. glauca (k = 0.0063) was significantly (p = 0.032) higher than that of P. australis (k = 0.0024). Litter decomposition rate had a significant (p < 0.01) relationship with water compositional parameters (water dissolved oxygen, temperature, chemical oxygen demand, and NH 3 -N). According to the results of our surface soil analysis, in plots with 1% salinity, values for total soil PLFAs, bacterial PLFAs, Gram-negative PLFAs, and fungal PLFAs were all higher after 270 days than after 120 days. Fungi were the principal microbial group responsible for leaf litter decay. Changes in the nutrient utilization of litter may result in changes in the allocation of resources for growth and reproduction, which suggests that artificial elevation of wetland nutrient content may mitigate the negative human impacts associated with climate change. This study demonstrated the effects of biotic (litter types, activities of microbial organisms) and abiotic (salinity, inundation) variables on halophyte litter decomposition in Yellow River Delta wetlands. [ABSTRACT FROM AUTHOR]

• Decomposition rates were measured among different salinity and inundation conditions. • Suaeda glauca decomposed faster than Phragmites australis in Yellow River Delta wetland. • Faster litter decomposition rate occurred in inundation environment. • The combined effect of salinity and inundation can significantly accelerate S. glauca litter decomposition rate. • Environment parameters and litter quality can interact and in turn affect the decomposition rate during the decay process. The main factors controlling plant litter decomposition rates are litter quality and environmental factors. We investigated how different salinity and inundation conditions influence the decomposition rate and how litter quality affects dynamic change during the decomposition process in the Yellow River Delta wetland in northeastern China. To do this, we designed a field experiment using the litter bag method to study two selected dominant halophyte species (Phragmites australis and Suaeda salsa). We found litter decomposed faster when inundated across a range of salinities. Both the water chemical oxygen demand and NH 3 -N concentration were inversely correlated with salinity. The ratio of nitrogen to phosphorous showed an upward trend during the process of decomposition. The decomposition rate increased during the later stage of the process. Under inundation conditions, the decomposition rate of only S. salsa showed a positive correlation with salinity. The study results suggest that moderately higher salinity would increase anaerobic decomposition owing to the combined effect of salinity and inundation. The implications of our findings may be used to further assess the impact of environmental parameters and litter quality on the decomposition rate in estuarine wetland and can help determine a strategy for wetland reparation and remediation. [ABSTRACT FROM AUTHOR]