2,4-D mediated moderation of aluminum tolerance in Salvinia molesta D. Mitch. with regards to bioexclusion and related physiological and metabolic changes

Abstract

We examined the efficacy of 2,4-dichlorophenoxy acetic acid (2,4-D; 500 µM) in enhancing the potential of Salvinia species for tolerance to aluminum (Al) toxicity (240 and 480 µM, seven days). Salvinia showed better efficacy in removal of toxicity of Al by sorption mechanism with changes of bond energy shifting on cell wall residues and surface structure. Plants recorded tolerance to Al concentration (480 µM) when pretreated with 2,4-D through adjustment of relative water content, proline content, osmotic potential, and improved the pigment fluorescence for energy utilization under Al stress. Photosynthetic activities with regards to NADP-malic enzyme and malic dehydrogenase and sugar metabolism with wall and cytosolic invertase activities were strongly correlated with compatible solutes. A less membrane peroxidation and protein carbonylation had reduced ionic loss over the membrane that was studied with reduced electrolyte leakage with 2,4-D pretreated plants. Membrane stabilization was also recorded with higher ratio of K⁺ to Na⁺, thereby suggesting roles of 2,4-D in ionic balance. Better sustenance of enzymatic antioxidation with peroxidase and glutathione metabolism reduced reactive oxygen species accumulation and save the plant for oxidative damages. Moreover, gene polymorphism for antioxidant, induced by 2,4-D varied through Al concentrations would suggest an improved biomarker for tolerance. Collectively, analysis and discussion of plant’s responses assumed that auxin herbicide could be a potential phytoprotectant for Salvinia as well as improving the stability to Al toxicity and its bioremediation efficacy.

Novelty Statement

In previous reports, aquatic weeds, particularly, from pteridophytic flora have been exercised, however, in less frequent. Aluminum (Al) toxicity, being a major problem, specifically with respect to cultivated crops like rice and vegetables, is a serious issue in alkaline soil. In context to growth of Salvinia in the areas of low lands where few important crops like rice are frequently cultivated. Therefore, Al toxicity with regards to rice cultivation in low land conditions, which is habitat for Salvinia, could be interesting. Thus, decontamination of low land for salinity with aquatic environment can be remediated with biological materials where Salvinia would be a choice. This would be something new in studies for the aquatic weeds over the existing database. Moreover, 2,4-dichlorophenoxy acetic acid (2,4-D) being a common herbicide in agricultural field that becomes more problematic with metal toxicity is another focus for physiological responses with Salvinia. The adoption and sustainability of Salvinia against 2,4-D may highlight insights for physiological activities would be the biomarker for herbicide toxicity.

Keywords:

• Aquatic fern
• cell wall modification
• gene polymorphism
• hyperaccumulation
• chlorophyll fluorescence
• phytoremediation
• redox homeostasis
• toxic metals

Acknowledgments

The experimental work was supported by the University Research Scholarship (URS), University of Kalyani, West Bengal, India, and the Department of Science and Technology, Govt. of India (DST –PURSE) Programme, DST, New Delhi, activated to University of Kalyani, Nadia, West Bengal, India. Dr. Indraneel Saha and Mr. Sayan Pal are acknowledged for their approaches from different angles.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

All data are available in this article.

Additional information

Funding

The experimental work was supported by the University Research Scholarship (URS), University of Kalyani, West Bengal, India, and the Department of Science and Technology, Govt. of India (DST –PURSE) Programme, DST, New Delhi, activated to University of Kalyani, Nadia, West Bengal, India.