Differential Effects of Natural Palygorskite and its Modified Form on Alleviation of Heavy Metals Toxicity to Tomato Grown in Soil Contaminated with Cd, Pb and Zn

Abstract

A field experiment was conducted to investigate differential effects of natural palygorskite (PAL) and its modified form (KH550-PAL) on the alleviation of heavy metals toxicity to tomatos grown in contaminated soil with Cd, Pb and Zn. Compared to heavy metal-contaminated soil without amendment, the application of natural palygorskite (PAL) or its modified form (KH550-PAL) significantly alleviated heavy metal toxicity to tomato. In addition, foliar malondialdehyde (MDA), hydrogen peroxide (H 2 O 2) and superoxide (O 2 •-) contents as well as non-photochemical quenching (NPQ) reduced by 89, 28, 71, and 81%, respectively, in the modified palygorskite treatment than in the natural palygorskite treatment. Similar patterns were observed in heavy metals uptake of tomato. Foliar superoxide dismutase (SOD), catalase (CAT) and glutathione reductase (GR) activities increased by 228, 196 and 238%, respectively, in the modified palygorskite treatment than in the natural palygorskite treatment. Thus, the application of the modified form (KH550-PAL) significantly ameliorated the oxidative stress via enhancing antioxidant defense and reducing thermal dissipation, which further improved photosynthetic electron transport of photosystem II and biomass accumulation of tomato. However, the dose of the modified palygorskite (KH550-PAL) was not enough to buffer negative effects of heavy metal toxicity to tomato growth in the experiment. It is suggested that the amendment dose should be used with great care in remediating contaminated soils with heavy metals. Thus, further experiments are needed by different rates of the modified palygorskite (KH550-PAL).

Comparison of Alteration in Growth, Physiological and Biochemical Attributes of Ten Maize (<i>Zea mays</i> L.) Varieties under Arsenic Stress: Susceptibility and Tolerance

“…It can damage the membrane properties, which is estimated from the increased MDA contents. Similar findings have been concluded in Arabdopsis thaliana exposed to As stress [61]. Malondialdehyde (MDA) is an indicator of occurrence of lipid peroxidation due to oxidative damage, which is detected in spinach leaves when grown in presence of As [62].…”

Single and Combined Effects of Cadmium and Lead on Seed Germination and Early Seedling Growth in <i>Rhus typhina</i>

“…As two primary antioxidative enzyme, previous studies revealed that SOD and POD play a relevant role in treatment of heavy metal enhances ROS formation [44,45]. SOD can eliminate O 2-, decrease peroxidation of membrane lipids and maintain cell membrane stability, and POD participate in the decomposition of H 2 O 2 [25,46]. In the present study and other studies showed that the activities of POD significantly increased and correlated with heavy metal stress, suggesting that plants adjusted their POD activity to protect membrane stability from heavy metal-induced oxidative damage [37,47] (Fig.…”