Copper phytoextraction by Salvinia cucullata: biochemical and morphological study

Area of Science:

• Environmental Science
• Plant Physiology
• Bioremediation

Background:

• Copper (Cu) contamination poses significant risks to aquatic ecosystems.
• Phytoremediation using aquatic plants offers a sustainable solution for metal removal.
• Salvinia cucullata is a fast-growing aquatic fern with potential for phytoremediation.

Purpose of the Study:

• To investigate the effects of copper on Salvinia cucullata's photosynthesis, antioxidant system, and anatomy.
• To evaluate the phytoremediation potential of Salvinia cucullata for copper-contaminated water.
• To determine the optimal copper concentration range for effective phytoremediation by this fern.

Main Methods:

• Hydroponic exposure of Salvinia cucullata to varying copper concentrations (10-30 mg/L) for 21 days.
• Measurement of photosynthetic pigments (chlorophyll, carotenoids), soluble proteins, and lipid peroxidation.
• Assay of antioxidant enzyme activities (superoxide dismutase, catalase, peroxidase) and analysis of plant anatomy and metal accumulation.

Main Results:

• Copper exposure led to significant reductions in chlorophyll, carotenoids, and proteins, with increased lipid peroxidation, indicating oxidative stress.
• Salvinia cucullata exhibited enhanced antioxidant enzyme activities (SOD, CAT, POD, APX) to mitigate reactive oxygen species (ROS).
• Optimal phytoremediation occurred at 10-15 mg/L Cu, with high accumulation (2956 ± 82.6 μg/g dw) and efficient root-to-shoot translocation (TF > 1). At higher doses (20-30 mg/L), an exclusion strategy was observed, with greater accumulation in roots.

Conclusions:

• Salvinia cucullata demonstrates significant copper phytoremediation potential, particularly at concentrations between 10-15 mg/L, due to efficient metal uptake, translocation, and robust stress tolerance mechanisms.
• The fern employs antioxidant defenses and anatomical adaptations, including high calcium peaks and stomatal closure, to mitigate copper-induced stress.
• Its widespread availability, rapid growth, and hardy physiology make Salvinia cucullata a suitable candidate for phytoremediation of copper-polluted aquatic environments.