Cadmium stress alleviation potential of Bruguiera cylindrica (L.) Blume enhances in combination with NaCl

Abstract

A hydroponic experiment in NaCl tolerant mangrove, Bruguiera cylindrica plantlets was done to investigate the interactive effects of CdCl₂+NaCl as well as the individual effects of CdCl₂. CdCl₂ alone results in enhanced level of cell membrane lipid peroxidation, damaging normal structure, and function of the membrane and there by leading to reduction of membrane stability index and thus severely promoting the electrolyte leakage than the combined treatment of CdCl₂+NaCl. Antioxidants greatly contribute to cope with the stress by scavenging ROS and were more prominent in individual stress than combined stress. B. cylindrica can be categorized as a highly tolerant mangrove species with a Tolerance Index (TI) of above 60% toward CdCl₂+NaCl (TI is 70 and 75% in leaf and root). But TI was only 63 and 67% in leaf and root, respectively, on exposure to CdCl₂ alone indicating that this plant is less tolerant to Cd alone. The existence of B. cylindrica depends on the heavy metals being introduced into the mangrove ecosystem and imparts a combination stress along with NaCl. In this regard, B. cylindrica survives up to 0.20 mM CdCl₂ along with NaCl. Thus, the high NaCl tolerance mechanisms in this mangrove species could be equally efficient in imparting tolerance toward high concentration of Cd along with NaCl and exhibits phytostabilization in polluted coastal wetlands.

Keywords:

• Cadmium
• combined stress
• NaCl
• phytostabilization
• scavenging mechanisms
• tolerance index

Acknowledgment

The authors greatly acknowledge Dr. V. Venkatesalu, Professor, Dept of Botany, Annamalai University for language correction and proof reading.

Authors contribution

P. Sruthi carried out the experiments and prepared the manuscript. J.T. Puthur took care of the study and designing of the work and edited the manuscript.

Disclosure statement

The authors declare that they have no conflict of interest.

Additional information

Funding

SP greatly acknowledges the financial assistance provided by the Department of Science and Technology, New Delhi; through INSPIRE fellowship (IF131045) for the research work. JTP acknowledges KSCSTE for funding through research grant from KSCSTE (KSCSTE/5179/2017-SRSLS).