Title : The rainfall effect and different levels of chemical elements on chlorophyll a fluorescence parameters in a Brazilian restinga species
Abstract:
The aim of this study was to analyze whether there was a relationship between rainfall and the concentration of bioavailable chemical elements that arrived in the coastal vegetation, from the tailings plume that reached the coast released in the Mariana disaster (Minas Gerais, Brazil) in 2015. It was also evaluated whether there was a direct relationship between the increase in rainfall and chemical elements on photosynthetic parameters. This dynamic was evaluated from the fluorescence of chlorophyll a in Byrsonima sericea, a shrubby species, which currently has been used as a model in restinga studies. The results showed that the photosynthetic performance of B. sericea varied seasonally and that there was a direct relationship between the concentration of trace elements in the soil and leaves and precipitation. This relationship determines variability between high metal concentrations (mainly Cu and Fe) and photosynthetic performance indices (PIabs and PItotal) and oxygen evolution complex (OEC) activity in PSII. Potentially combined effects of high concentrations of elements and rainfall regimes caused changes in parameters related to quantum efficiency, specific energy fluxes and performance indices. The data presented in this study conclusively proved that Byrsonima sericea responds to different environmental conditions and that the dry season was more harmful to plants than the wet season in terms of impacts of rainfall regime and metal availability; metal availability also varied according to rainfall patterns and transport via marine aerosols. In addition to the natural stress conditions experienced by the restinga vegetation, such as alternating rigorous rainfall regimes and dry periods, the addition of an imbalance factor such as the presence of trace elements in the soil and leaf tissue, resulted in marked alterations in the photosynthetic metabolism of B. sericea. Finally, the analyzes indicated the use of chlorophyll fluorescence as a fast and accurate analysis, to understand the impacts of trace elements in natural ecosystems affected by events such as the rupture of the Fundao dam.
What will audience learn from your presentation?
• Chlorophyll fluorescence studies have shown that the tool can be used to quickly and non-destructively analyze vegetation status;
• The combined analysis of environmental conditions and physiological responses allows a more accurate interpretation of vegetation status and consequently its vitality;
• Analyzes showed that some conditions are physiologically more unfavorable, as is the case when excessive amounts of some trace elements are combined with high precipitation, promoting changes in the structure of the photosynthetic apparatus.
