Synergistic and concentration-dependent toxicity of multiple heavy metals compared with single heavy metals in Conocarpus lancifolius

Abstract

While heavy metals (HMs) naturally occur in soil, anthropogenic activities can increase the level of these toxic elements. Conocarpus lancifolius Engl. (Combretaceae) was investigated as a potential phytoremediator of soils contaminated with HM containing crude oil. This study assessed the potential of C. lancifolius (CL), a locally available plant species in Kuwait, for resolving local issues of the HM-contaminated soils. The absorption, accumulation, and distribution of three toxic HMs (Cd, Ni, and Pb) and essential metals (Fe, Mg, and metalloid Se) were examined, and their role in plant toxicity and tolerance was evaluated. Conocarpus lancifolius plants were exposed to two different concentrations of single and mixed HMs for 30 days. The accumulation of HMs was determined in the roots, leaves, stems, and the soil using ICP/MS. Biomass, soil pH, proline and protein content, and bioaccumulation, extraction, and translocation factors were measured. The bioaccumulation, extraction, and transcription factors were all >1, indicating CC is a hyperaccumulator of HM. The HM accumulation in CL was concentration-dependent and depended on whether the plants were exposed to individual or mixed HMs. The C.C leaves, stems, and roots showed a significant accumulation of antioxidant constituents, such as proline, protein, Fe, Mg, and Se. There was an insignificant increase in the soil pH, and a decrease in plant biomass and a significant increase in protein, and osmoprotective-proline as a result of the interaction of mixed heavy metals that are more toxic than single heavy metals. This study indicates that C. lancifolius is a good candidate for phytoremediation of multiple HM-contaminated soils. Further studies to establish the phyto-physiological effect of multiple heavy metals are warranted.

Foliar Application of Salicylic Acid Improves Water Stress Tolerance in Conocarpus erectus L. and Populus deltoides L. Saplings: Evidence from Morphological, Physiological, and Biochemical Changes

“…Leaves are shiny on both sides due to the formation of trichomes and root formation is profuse and fibrous in nature [ 35 ]. Conocarpus has the ability to grow in compacted soils and can also tolerate drought [ 36 ], therefore, the species is used for the reforestation of arid to semiarid areas. Populus deltoides belongs to the family Salicaceae .…”

Adsorptive behaviour of rutile phased titania nanoparticles supported on acid-modified kaolinite clay for the removal of selected heavy metal ions from mining wastewater

“…Among these is water pollution, which endangers the survival of both plants and animals in the present twenty-first century due to exposure to different contaminants. Toxic pollutants of several types are being released into the water bodies causing considerable damages to the human organs, plants and distortion of the ecosystem (Manisalidis et al 2020;Redha et al 2021). These pollutants are released as by-products from the operations of metallurgy, electroplating, painting, pharmaceutical and mining industries (Wang et al 2021).…”

Interspecific Differences in Physiological and Biochemical Traits Drive the Water Stress Tolerance in Young Morus alba L. and Conocarpus erectus L. Saplings

“…Conocarpus erectus L. ( C. erectus ) belong to the family Combretaceae . The species is native to riverine areas of Somalia, Djibouti, Yemen, horn of Africa, Arabian Peninsula, and South Asia [ 26 ]. C. erectus has also been recognized in several countries as a reliable candidate to withstand different harsh environments, including high temperature, salinity and drought stress of the tropical and sub-tropical regions [ 27 ].…”

“…C. erectus has also been recognized in several countries as a reliable candidate to withstand different harsh environments, including high temperature, salinity and drought stress of the tropical and sub-tropical regions [ 27 ]. Due to its fast growth, long hairy and deep roots, high nutrients and metals uptake and large biomass production potential, this species can also be important to revegetate the arid to semi-arid region [ 26 ]. However, evidencing the drought tolerance mechanism of these species is important before recommending these species in revegetation programs.…”