title: Stress acclimation and particulate matter accumulation in Pinus sylvestris saplings affected by moderate combinations of urban stressors.
abstract: To predict how the function of urban vegetation and the provision of ecosystem services respond to combinations of natural and anthropogenic drivers, a better understanding of multiple stress interactions is required. This study tested combined effects of moderate levels of drought, soil salinity and exposure to diesel exhaust on parameters of physiology, metabolism, morphology and growth of Pinus sylvestris L. saplings. We found that plant responses were primarily dominated by single stressors and a few two-way interactions. Stressor combinations did not have considerable additional negative effects on plant performance compared to single stressors. Hence, synergistic and antagonistic interactions were rare and additive effects frequent. Drought cycles caused most negative effects, from chlorophyll a fluorescence and epicuticular wax content to growth responses, while soil salinity caused fewer negative effects but contributed to reduction in fine root growth and fluorescence parameters at low air contamination. Interestingly, the air contamination alone had only marginal effects on plant morphology and growth, but contributed an antagonistic effect, dampening the negative effect of drought and salinity on the maximum quantum efficiency of PSII photochemistry (Fv/Fm) and fine root biomass. Although, these effects were moderate, it appears that exhaust exposure had a cross-acclimation effect on plant responses to drought and salinity. We also found that salinity had a negative effect on the accumulation of particulate matter on shoots, illustrating that the plant stress situation can affect the provisioning of certain ecosystem services like pollution attenuation. These findings have implications for the understanding of the complex natural and anthropogenic stress situation of urban, and how to maintain the ecological functions and delivery of ecosystem services.
authors.affiliation: Urban Greening and Environmental Engineering, The Norwegian Institute of Bioeconomy Research, Pb. 115, 1431 Ås, Norway. Electronic address: hans.martin.hanslin@nibio.no.
authors.forename: Hans Martin
authors.initials: HM
authors.lastname: Hanslin
authors.affiliation: Laboratory of Basic Research in Horticulture, Faculty of Horticulture, Biotechnology and Landscape Architecture, Warsaw University of Life Sciences - SGGW, Nowoursynowska 159, 02-776 Warsaw, Poland. Electronic address: arkadiusz.przybysz@sggw.pl.
authors.forename: Arkadiusz
authors.initials: A
authors.lastname: Przybysz
authors.affiliation: Urban Greening and Environmental Engineering, The Norwegian Institute of Bioeconomy Research, Pb. 115, 1431 Ås, Norway. Electronic address: rune.slimestad@nibio.no.
authors.forename: Rune
authors.initials: R
authors.lastname: Slimestad
authors.affiliation: Urban Greening and Environmental Engineering, The Norwegian Institute of Bioeconomy Research, Pb. 115, 1431 Ås, Norway. Electronic address: arne.sabo@nibio.no.
authors.forename: Arne
authors.initials: A
authors.lastname: Sæbø
mesh_terms: D000064:Acclimatization; D002734:Chlorophyll; D000077194:Chlorophyll A; D002947:Cities; D055864:Droughts; D052638:Particulate Matter / Q000378:metabolism*; D041605:Pinus sylvestris / Q000378:metabolism*; D018515:Plant Leaves; D054712:Salinity; D012987:Soil / Q000737:chemistry; D013312:Stress, Physiological; D001335:Vehicle Emissions; D014867:Water
chemical_list: D052638:Particulate Matter; D012987:Soil; D001335:Vehicle Emissions; D014867:Water; D002734:Chlorophyll; D000077194:Chlorophyll A
keywords: Additive stress responses; Air contamination; Cross-acclimation; Drought; Exhaust exposure; Multiple stresses; Soil salinity