Effects of calcium at toxic concentrations of cadmium in plants

Abstract

This review provides new insight that calcium plays important roles in plant growth, heavy metal accumulation and translocation, photosynthesis, oxidative damage and signal transduction under cadmium stress. Increasing heavy metal pollution problems have raised word-wide concerns. Cadmium (Cd), being a highly toxic metal, poses potential risks both to ecosystems and human health. Compared with conventional technologies, phytoremediation, being cost-efficient, highly stable and environment-friendly, is believed to be a promising green technology for Cd decontamination. However, Cd can be easily taken up by plants and may cause severe phytotoxicity to plants, thus limiting the efficiency of phytoremediation. Various researches are being done to investigate the effects of exogenous substances on the mitigation of Cd toxicity to plants. Calcium (Ca) is an essential plant macronutrient that involved in various plant physiological processes, such as plant growth and development, cell division, cytoplasmic streaming, photosynthesis and intracellular signaling transduction. Due to the chemical similarity between Ca and Cd, Ca may mediate Cd-induced physiological or metabolic changes in plants. Recent studies have shown that Ca could be used as an exogenous substance to protect plants against Cd stress by the alleviation of growth inhibition, regulation of metal uptake and translocation, improvement of photosynthesis, mitigation of oxidative damages and the control of signal transduction in the plants. The effects of Ca on toxic concentrations of Cd in plants are reviewed. This review also provides new insight that plants with enhanced Ca level have improved resistance to Cd stress.

Phytostabilization of Cd and Pb in Highly Polluted Farmland Soils Using Ramie and Amendments

“…Ca was involved in photosynthesis processes, such as photosynthetic electron flow and light-dependent metabolic reactions [44,45]. In the Cd-contaminated medium, the application of Ca could restore the photosynthesis of plants under Cd stress [46]. This deduction was consistent with the results of the current experiment.…”

Effects of Calcium on the Alleviation of Cadmium Toxicity in <i>Salix matsudana</i> and Its Effects on Other Minerals

“…Ca is an essential plant macronutrient that involved in various plant physiological processes, such as plant growth and development, cell division, cytoplasmic streaming, photosynthesis and intracellular signaling transduction [23,27,28]. Some research works demonstrated that Ca could regulate a range of activities within the cell, such as cell division and elongation, cytoplasmic streaming, photomorphogenesis and plant defense against environmental stresses [29][30][31][32][33].…”

“…Several reports indicated that Ca could compete with Cd in plants to increase the tolerance of plants to heavy metals and reduce the damage caused by heavy metals to plants [34,35]. Ca alleviates Cd-induced oxidative stress in plants by scavenging reactive oxygen species (ROS), increasing antioxidant levels and enhancing antioxidant enzymes activities [28]. Cd and Ca have similar ionic Values followed by different letters differ significantly from each other (P<0.05, t-test).…”

CAX1 suppresses Cd‐induced generation of reactive oxygen species in Arabidopsis halleri

“…When considering the underlying mechanism, one needs to explain not only the suppression of ROS accumulation by AhCAX1 but also the strict dependence on low external Ca 2+ . Elevated Ca 2+ concentration can potentially have a protective effect on Cd 2+ ‐exposed cells by partially blocking Cd 2+ uptake (Huang et al, ; Tian et al, ). Shoot and root ionome profiles showed efficient Cd root‐to‐shoot translocation and indeed a reduction in overall Cd accumulation in high Ca 2+ medium (Figure ) that was similar in extent to the difference reported for Sedum alfredii grown in either 0.5 or 2 mM Ca 2+ (Tian et al, ).…”