Effect of Cadmium Toxicity on Growth, Oxidative Damage, Antioxidant Defense System and Cadmium Accumulation in Two Sorghum Cultivars

Abstract

Heavy metal stress is a leading environmental issue reducing crop growth and productivity, particularly in arid and semi-arid agro-ecological zones. Cadmium (Cd), a non-redox heavy metal, can indirectly increase the production of reactive oxygen species (ROS), inducing cell death. A pot experiment was conducted to investigate the effects of different concentrations of Cd (0, 5, 25, 50, 100 µM) on physiological and biochemical parameters in two sorghum (Sorghum bicolor L.) cultivars: JS-2002 and Chakwal Sorghum. The results showed that various concentrations of Cd significantly increased the Cd uptake in both cultivars; however, the uptake was higher in JS-2002 compared to Chakwal Sorghum in leaf, stem and root. Regardless of the cultivars, there was a higher accumulation of the Cd in roots than in shoots. The Cd stress significantly reduced the growth and increased the electrolyte leakage (EL), hydrogen peroxide (H2O2) concentration and malondialdehyde (MDA) content in both cultivars, but the Chakwal Sorghum showed more pronounced oxidative damage than the JS-2002, as reflected by higher H2O2, MDA and EL. Moreover, Cd stress, particularly 50 µM and 100 µM, decreased the activity of different antioxidant enzymes, including superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT). However, the JS-2002 exhibited higher SOD, POD and CAT activities than the Chakwal Sorghum under different Cd-levels. These findings revealed that JS-2002 had a stronger Cd enrichment capacity and also exhibited a better tolerance to Cd stress due to its efficient antioxidant defense system than Chakwal Sorghum. The present study provides the available information about Cd enrichment and tolerance in S. bicolor, which is used as an important agricultural crop for livestock feed in arid and semi-arid regions.

Ameliorative Effects of Exogenous Proline on Photosynthetic Attributes, Nutrients Uptake, and Oxidative Stresses under Cadmium in Pigeon Pea (Cajanus cajan L.)

“…Cadmium stress-induced oxidative stress in pigeon pea was measured by the elevated contents of hydrogen peroxide, thiobarbituric acid reactive substances, and electrolyte leakage (Figure 2). Our findings are consistent with previous studies, where similar oxidative damage under cadmium exposure in other plant species has been reported [14][15][16].…”

“…This boost in antioxidant enzymes in pigeon pea reflects the enzymatic mechanisms in response to cadmium-induced oxidative stresses. Previous studies have reported similar increases in antioxidant enzymes under Cd stress in other plant species [15,24,71].…”

“…These growth-inhibiting effects of Cd on pigeon pea may be attributed to the significant decrease in photosynthetic activities, nutrient deficiency, and excessive ROS production (Tables 1 and 2; Figure 1). Previous studies have reported similar reduced growth attributes in other plant species due to cadmium stress [14,15,52,53]. Photosynthesis is plants' life-sustaining process and is often sensitive to metal stresses.…”

“…Its existence in agricultural soil poses a severe threat due to its entry into the food chain, thus damaging animal and human health [11][12][13]. Elevated cadmium quantities in plants delay seed germination, induce growth inhibition, and reduce productivity [14][15][16]. It plays an influential role in the uptake, transport, and distribution of nutrients [17][18][19][20].…”

Effect of Dissolve Organic Matter Nn Cd Contaminated Cotton (Gossypium Hirsutum L.) Growth and Cd Uptake

“…Under heavy metal stress, plant cells produce ROS and gradually accumulate them, damaging the cell structure and slowing down plant growth (Hassan et al 2020). For this reason, the antioxidant system consisting of enzymes such as superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) in plants scavenges ROS to ensure normal plant growth (Shahid et al 2014).…”