8 research outputs found
A REVIEW OF THE IMPACT OF AIR POLLUTION ON THE INFECTION AND MORTALITY RATES DUE TO COVID-19
In the late February 2020, the first positive cases of the novel coronavirus, COVID-19, were confirmed in Iran, and the World Health Organization updated the
status of the global outbreak from epidemic to pandemic in mid-March 2020. The rapid outbreak of the virus intervened a significant portion of socioeconomic activities, leaving behind some serious questions on the main factors intensifying the infection and the morality rates. Although the primary impacts of the outbreak have been extensively explored at the global and regional scales since its emergence, the impacts of the environment on the viral spread are still poorly understood. The goal of this paper is to review the most recent scientific findings on the spatiotemporal correlation between the air pollution and the mortality rate due to COVID-19. These researches are based on statistical analysis of the ground and satellite-based recorded data on PM2.5,PM10, and NOx across the United States, China, Italy, and England. The majority of these studies also consider data on population intensity, meteorological variables, migration rate, age, and health service quality to guarantee the validity of the findings by excluding the possible impacts imposed by these stressors. The results suggest that there exists a significant positive correlation between the concentration of the aforementioned air pollutants and the infection and mortality rates due to COVID-19. While long-term exposure to NOx has been associated with hypertension, heart and cardiovascular diseases, and chronic obstructive pulmonary disease, high concentration of PM2.5 and PM10 pollutants additionally enhances the mortality rate by facilitating the transmit of pathogenic agents through the fine particulate matters in the air. Regarding the drastic air pollution condition during the cold seasons in the most populated cities across Iran, the conclusions of this study can guide policy makers towards an effective planning and management of the COVID-19 crisis in such seasons
Impact of long-term organic and mineral fertilization on rhizosphere metabolites, root-microbial interactions and plant health of lettuce.
Fertilization management can affect plant performance and soil microbiota, involving still poorly understood rhizosphere interactions. We hypothesized that fertilization practice exerts specific effects on rhizodeposition with consequences for recruitment of rhizosphere microbiota and plant performance. To address this hypothesis, we conducted a minirhizotron experiment using lettuce as model plant and field soils with contrasting properties from two long-term field experiments (HUB-LTE: loamy sand, DOK-LTE: silty loam) with organic and mineral fertilization history. Increased relative abundance of plant-beneficial arbuscular mycorrhizal fungi and fungal pathotrophs were characteristic of the rhizospheres in the organically managed soils (HU-org; BIODYN2). Accordingly, defense-related genes were systemically expressed in shoot tissues of the respective plants. As a site-specific effect, high relative occurrence of the fungal lettuce pathogen Olpidium sp. (76–90%) was recorded in the rhizosphere, both under long-term organic and mineral fertilization at the DOK-LTE site, likely supporting Olpidium infection due to a lower water drainage potential compared to the sandy HUB-LTE soils. However, plant growth depressions and Olpidium infection were exclusively recorded in the BIODYN2 soil with organic fertilization history. This was associated with a drastic (87–97%) reduction in rhizosphere abundance of potentially plant-beneficial microbiota (Pseudomonadaceae, Mortierella elongata) and reduced concentrations of the antifungal root exudate benzoate, known to be increased in presence of Pseudomonas spp. In contrast, high relative abundance of Pseudomonadaceae (Gammaproteobacteria) in the rhizosphere of plants grown in soils with long-term mineral fertilization (61–74%) coincided with high rhizosphere concentrations of chemotactic dicarboxylates (succinate, malate) and a high C (sugar)/N (amino acid) ratio, known to support the growth of Gammaproteobacteria. This was related with generally lower systemic expression of plant defense genes as compared with organic fertilization history. Our results suggest a complex network of belowground interactions among root exudates, site-specific factors and rhizosphere microbiota, modulating the impact of fertilization management with consequences for plant health and performance