Title : Chlorophyll fluorescence excitation techniques reveal community-level physiological characteristics of Brazilian Coastal Restinga
Abstract:
The restinga is a coastal ecosystem characterized by the zonation of different functional groups of plants, which are grouped due to the impact of limiting environmental conditions, which, in turn, are attenuated along a spatial gradient in the sea - continent direction. We believe that these conditions are able to bring together similar physiological traits at the community level, therefore, this study has as main objective to provide information about functional characteristics of plants through the analysis of fluorescence signals in two different communities. For this, we developed a field quantitative fluorometry protocol using the multispectral fluorescence induction sensor (Multiplex, Force-A, France) combined with transient chlorophyll fluorescence analysis (Hand-PEA Hansatech Instruments, United Kingdom). Measurements took place in 10 species, five species in each community, herbaceous and shrubby. The results show that plants located in the herbaceous community are characterized by having higher levels of flavonoids, indicating the presence of a metabolic framework capable of promoting tolerance and influencing the efficiency of energy use, as also seen in the highest average values of photochemical performance indexes. On the other hand, lower values were recorded for the nitrogen balance indexes, which was attributed to limiting conditions of nitrogen in coastal soils. As for the shrub community, the highest mean values were found for nitrogen balance, and also for the anthocyanin index, which is possibly linked to defense mechanisms against herbivory. In contrast to the other parameters, the weighted average of the chlorophyll indexes remained practically unchanged and were not informative in the functional characterization of the communities. Proximal sensing using fluorescence techniques proved to be an efficient method to measure physiological characteristics in plant communities, and may complement other methods in functional ecology, providing environmental indicators of the state of the restinga ecosystem.
What will audience learn from your presentation?
- Fluorescence signals analysis is an efficient non-destructive technique of species screening and provide information about functional characteristics of plants;
- Restinga plant mosaic is composed of ecologically plastic species with similar physiological characteristics at the community level, which result in specifics spatial zonation in response to the its different environmental conditions;
- Understanding the capacity of plants to respond to variations in the availability of resources is fundamental and would allow an increased comprehension of the balance and dynamics of ecosystem communities, especially for recovery and management projects of impacted areas.
