Particulate matter accumulation – further differences between native Prunus padus and non-native P. serotina

Particulate matter (PM) is one of the most harmful inhaled pollutants. Where pollutants have been emitted into the atmosphere, the most effective method for cleaning the air is through phytoremediation, whereby plants act as biological filters. PM has a negative impact on plants, but knowledge of PM effects on the photosynthetic apparatus is limited. In European forests, species of the genus Prunus L. play a key role in the composition of the forest understory and urban as well as industrial plantings. Shrubs of the native P. padus L. and closely-related invasive alien P. serotina Ehrh. are particularly widespread. Thus, both are good model species in which to study the impact of PM pollution. The aim of this study was to assess the accumulation of PM in the context of leaf morphology and amount of epicuticular waxes on foliage, and the efficiency of the photosynthetic apparatus of P. padus and P. serotina. The study was conducted under controlled conditions using two variants of dust, cement and roadside PM. In addition, we analyzed the absorption of dust by leaves dividing it into three fractions by size (10−100 μm, 2.5−10 μm and 0.2−2.5 μm). Results showed that both P. padus and P. serotina accumulate PM mostly on the surface of their leaves (SPM), rather than in the wax layer (WPM). P. padus accumulated higher amounts of PM than did P. serotina. The higher presence of PM on leaves of P. padus resulted in a reduction of the efficiency of the photosynthetic apparatus, manifested by lower rates of photosynthesis and chlorophyll a fluorescence, coinciding with an increased stomatal resistance. A strong negative correlation was found between the amount of PM accumulation and the efficiency of the photosynthetic apparatus in P. padus, but not in P. serotina. We have concluded that alien P. serotina is more tolerant to the conditions of stress caused by PM pollution than is the native P. padus, which may partly explain its success in the invasion in Europe.