Development of a toxicophenomic index for trace element ecotoxicity tests using the halophyte Juncus acutus: Juncus-TOX

Marine and coastal ecosystems are the ultimate sink of many contaminants from anthropogenic activities, such as trace elements. Although several ecotoxicological tests available using autotrophic organisms, none focus on marine plants. Juncus acutus has already showed that it is a good candidate for studies, providing set contamination biomarkers. The present work evaluates application pulse amplitude modulated (PAM) fluorometry derived variables to develop an integrated biomarker response index (Juncus-TOX) classify exposure J. seedlings element contamination. Trace (Zn, Cu, Cd, Ni, Pb, As) led reduced seedling growth, confirming toxic effects imposed by tested elements concentrations. Observing Kautsky curves each metal exposure, abrupt fluorescence decrease could be observed at high Pb Ni concentrations, while As caused modification in shape curve, increasing intensity J-step. These changes have consequences whole variable dataset extracted curves. With exception exposed Zn, generated proved classifiers level which plants were subjected. Moreover, phenomological energy fluxes attained this bio-optical approach highlight photobiological impacts different elements, together with metal-substituted chlorophyll generation, support morphometric changes. Cadmium increased significantly absorbed dissipated fluxs (ABS/CS DI/CS). Regarding trapped electron transport flux (TR/CS ET/CS) there was substantial decreased highest concentrations Pb. 42 parameters JIP-test included toxicophenomic (Juncus-TOX). All computed versions correlations exogenous dose. Thus, Juncus-TOX efficient tool assays acutus, highlighting potential use species future halophyte model ecotoxicology.