The Strong and the Stronger: The Effects of Increasing Ozone and Nitrogen Dioxide Concentrations in Pollen of Different Forest Species

Abstract

The knowledge of pollen sensitivity and tolerance to stress factors such as air pollution is important for forest sustainability, ensuring the most efficient production with the highest benefits and lowest resource losses. This study intended to evaluate the influence of common air pollutants in four forest trees species, Betula pendula Roth, Corylus avellana L., Acer negundo L. and Quercus robur L., through a comparative analysis at the same experimental conditions. We aimed to investigate the effect that may occur in pollen fertility, protein content, oxidative stress and wall composition after exposure in vitro to ozone and nitrogen dioxide at concentration levels for vegetation protection in Europe. Our results suggest changes in pollen viability, protein content and differential sensitivity related to ROS synthesis, NADPH oxidase activity, as well as in wall composition. The results indicate that NO2 exposure affected more the pollen species studied mostly at the highest concentration exposure. As for ozone, there were less significant differences between samples; however, a different behavior occurs in O3 expositions, where the most influence happens at the legal limit for vegetation protection in Europe. Our study showed that significant pollen functions could be compromised even at common air pollutant’s concentrations.

Interaction between Air Pollutants and Pollen Grains: Effects on Public and Occupational Health

“…To this purpose, morphological analysis of the pollen grains is very important. Several studies showed changes in the morphological structure of the cell wall such as shrinkage, thinning, rupture of exine, dilatation of the intine wall and in the pollen wall's constituents such as sporopollenin that can be determinant in the resistance of pollen grains to environmental pollution [34,[43][44][45] (Figure 2). particular attention.…”

“…To this purpose, morphological analysis of the pollen grains is very important. Several studies showed changes in the morphological structure of the cell wall such as shrinkage, thinning, rupture of exine, dilatation of the intine wall and in the pollen wall's constituents such as sporopollenin that can be determinant in the resistance of pollen grains to environmental pollution [34,43,44,45] (Figure 2). In an interesting study, the researchers demonstrated the shrinkage of exine of many species of pollen (Cyperus rotundus, Syzygium cumini, Hyptis suaveolens, Cocos nucifera, Acacia nilotica, Eucalyptus tereticornis, Azadirachta indica and Zea mays) that had been exposed to high concentrations of some pollutants of anthropogenic origin (PMx particles, SO2 and NOx) [46].…”

“…At the molecular level, air pollutants have a relatively strong oxidative role that affects biomolecules such as proteins (consisting of their nitration and oxidation), lipids (change in content, composition and quantitative properties) and nucleic acids (mutation in the genetic material), interfering with pollen germination and elongation of the pollen tube [31][32][33]. In the literature, several studies highlight that each plant species may have a different susceptibility/tolerance to the atmosphere's pollution levels such as NO 2 and O 3 , and each species (i.e., Betula, Ambrosia, Birch, Quercus) shows different reactions depending on the pollutant type and concentration [4,24,[34][35][36]. However, these effects of air pollutants on pollen species must also be considered in the context of vegetation and the influence of meteorological conditions [14,34]; therefore, the sensitivity of people in different areas changes with pollen species [13,37].…”

“…In the literature, several studies highlight that each plant species may have a different susceptibility/tolerance to the atmosphere's pollution levels such as NO 2 and O 3 , and each species (i.e., Betula, Ambrosia, Birch, Quercus) shows different reactions depending on the pollutant type and concentration [4,24,[34][35][36]. However, these effects of air pollutants on pollen species must also be considered in the context of vegetation and the influence of meteorological conditions [14,34]; therefore, the sensitivity of people in different areas changes with pollen species [13,37]. To this purpose, in this work, we have investigated, with attention especially on the most recent studies, the effects of air pollutants on pollen grains to understand how the interactions between pollen and air pollutants affect public and occupational health in relation to the factors (i.e., climate change, urbanization, pollens species) that play a role in this context.…”

Quantitative assessment of coagulation of atmospheric particles onto airborne birch pollen grains

“…Alterations of BPGs due to atmospheric biochemical reactions with ozone or nitrogen dioxide have been highlighted (Sénéchal et al, 2015). Gaseous air pollutants modify the lipid and protein fraction of BPGs (Farah et al, 2021;Pereira et al, 2021;. Not only pollen grains (PGs) can be modified by air pollution, but there are clear qualitative evidences that allergenic PGs can also act as carriers of pollutants, both adsorbed gases and coagulated particles (Okuyama et al, 2007;Zhu et al, 2018).…”