Differential Uptake and Translocation of Cadmium and Lead by Quinoa: A Multivariate Comparison of Physiological and Oxidative Stress Responses

Abstract

Contamination of soils with cadmium (Cd) and lead (Pb) has emerged as a serious environmental issue that reduces crop productivity. However, the metals tolerance and accumulation potential of quinoa (Chenopodium Quinoa Willd) under the combined stress of Cd and Pb has not yet been explored. In the present hydroponic study, the physiological and biochemical characteristics of quinoa exposed to Cd and Pb were explored. Four-week-old plants of quinoa genotype ‘Puno’ were grown under different concentrations of Cd (0, 50 and 100 µM), Pb (0, 250 and 500 µM) alone as well as in combinations. The results showed that with increasing Cd and Pb levels in the nutrient solution, the plant biomass, stomatal conductance and chlorophyll contents were decreased. However, the concurrent application of higher concentrations of Cd (100 µM) and Pb (500 µM) caused even more reduction in the plant biomass (more than 50% than the control) and physiological attributes. The combined application of Pb and Cd caused oxidative stress through an overproduction of H2O2 (10-fold) and TBARS (12.5-fold), leading to decrease in membrane stability (52%). The oxidative stress was alleviated by a 7-fold, 10-fold and 9-fold overactivation of superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT), respectively. An excessive uptake of Cd resulted in a limited uptake of Pb and K in the roots and shoots of quinoa plants. The Cd and Pb tolerance and uptake potential of Puno showed its ability to stabilize Cd and Pb in co-contaminated soils.

Salicylic Acid- and Potassium-Enhanced Resilience of Quinoa (Chenopodium quinoa Willd.) against Salinity and Cadmium Stress through Mitigating Ionic and Oxidative Stress

“…It was observed that both the salinity and Cd decreased plant growth attributes; however, their combined stress was more detrimental for the plant growth of quinoa. A decline in the growth of quinoa and other plants under Cd stress is well reported [6,20,21]. Cadmium, after being taken up by plant roots, is accumulated in different parts of the plants [22].…”

“…A more severe decline in plant growth under the combined stress of Cd and salinity might be due to the disturbance in photosynthetic activities, damage to the cell membrane structure, and disruption in water balance [24]. Moreover, Cd and salt stress affected many essential processes of plants such as the over-production of ROS, decrease in stomatal conductance and pigment contents, and disturbance in the uptake of essential nutrients including K [6,21].…”

Effects of different concentrations of biochar amendments and Pb toxicity on rhizosphere soil characteristics and bacterial community of red clover (Trifolium pretense L.)

“…Lead (Pb) is one of the most common HM pollutants in the environment. The Pb concentration is approximately 50 mg/kg in the soil in nature ( Bamagoos et al., 2022 ). However, due to the use of paint, Pb-containing gasoline and other Pb-containing products and the lack of effective treatment methods, the Pb concentration in the environment is much higher than the recommended safe concentration ( Salam et al., 2016 ).…”

A Study on the Behavior of Cadmium in the Soil Solution–Plant System by the Lysimeter Method Using the 109Cd Radioactive Tracer

“…In uncontaminated soils, its content in dry plant biomass and grain is in the range of 0.01–0.9 mg kg −1 [ 30 , 31 , 32 ]. It is known that Cd is a toxicant, carcinogen and teratogen [ 9 , 32 , 33 ].…”