Molecular and Physiological Mechanisms of Andira fraxinifolia under Copper and Zinc Stress
Name: LEONARDO ARENAS CAVADAS BUAIZ DE LIMA
Publication date: 19/02/2026
Examining board:
Name |
Role |
|---|---|
| DIOLINA MOURA SILVA | Presidente |
| JOSE AIRES VENTURA | Examinador Interno |
| VITOR DE LAIA NASCIMENTO | Examinador Externo |
Summary: Environmental contamination by heavy metals, especially copper (Cu) and zinc (Zn), has intensified in coastal ecosystems associated with the Atlantic Forest, such as restinga environments, highlighting the need to identify native species capable of tolerating and mitigating these impacts. In this context, the present study aimed to evaluate the tolerance capacity of Andira fraxinifolia Benth. to isolated and combined exposure to Cu and Zn, integrating molecular and physiological mechanisms, with a view to its biotechnological potential and application in phytoremediation and restoration strategies for degraded areas.
Young plants were cultivated under greenhouse conditions and subjected to increasing concentrations of Cu, Zn, and their combinations, at levels significantly higher than those typically found in natural environments, using Hoagland and Arnon nutrient solution as the control. The following parameters were evaluated: relative expression of metallothionein genes (MT1, MT2, and MT3), metal accumulation in leaf tissues, contents of phenolic compounds and total flavonoids, antioxidant capacity assays, lipid peroxidation, photosynthetic pigment contents, and chlorophyll a fluorescence parameters. Molecular analysis revealed distinct temporal patterns of metallothionein expression, characterized by early induction of MT1 and MT2 and late, sustained activation of MT3, indicating a coordinated and dynamic detoxification response throughout the stress period. The results indicated that, despite some alterations induced by high concentrations of Cu and Zn, A. fraxinifolia plants remained functionally active throughout the entire experimental period. Zinc promoted responses associated with increased oxidative stress and changes in photochemical efficiency, whereas copper more consistently stimulated the activation of antioxidant pathways, particularly those related to the synthesis of flavonoids and phenolic compounds. Combined exposure to the metals intensified metabolic responses, demonstrating the species’ ability to modulate its defense mechanisms under co-exposure conditions. Overall, the results suggest that Andira fraxinifolia exhibits high molecular and physiological plasticity in response to Cu and Zn exposure, tolerating concentrations far exceeding those found in its natural habitat without mortality. These findings highlight the species as a promising candidate for phytoremediation and phytostabilization strategies in heavy metal– contaminated coastal ecosystems.
