Bentonite and Biochar Mitigate Pb Toxicity in Pisum sativum by Reducing Plant Oxidative Stress and Pb Translocation

Abstract

Lead (Pb)-polluted soils pose a serious threat to human health, particularly by transmitting this heavy metal to the food chain via the crops grown on them. The application of novel amendments in Pb-polluted soils can significantly reduce this problem. In this research, we report the effects of various organic and inorganic amendments i.e., bentonite (BN), biochar (BR), lignin (LN), magnesium potassium phosphate cement (CM) and iron hydroxyl phosphate (FeHP), on the Pb bioavailability in Pb-polluted soil, upon Pb distribution in shoots, roots, grain, the translocation factor (TF) and the bioconcentration factor (BCF) of Pb in pea (Pisum sativum L.) grain. Furthermore, effects of the said amendments on the plant parameters, as well as grain biochemistry and nutritional quality, were also assessed. Lead pollution significantly elevated Pb concentrations in roots, shoots and grain, as well as the grain TF and BCF of Pb, while reducing the nutritional quality and biochemistry of grain, plant height, relative water content (RWC), chlorophyll contents (chl a and chl b) and the dry weight (DW) of shoot, root and grain. The lowest Pb distribution in shoots, roots and grain were found with BN, FeHP and CM, compared to our control. Likewise, the BN, FeHP and CM significantly lowered the TF and BCF values of Pb in the order FeHP > CM > BN. Similarly, the highest increase in plant height, shoot, root and grain DW, RWC, chl a and chl b contents, grain biochemistry and the micronutrient concentrations, were recorded with BR amendment. Biochar also reduced grain polyphenols as well as plant oxidative stress. Given that the BR and BN amendments gave the best results, we propose to explore their potential synergistic effect to reduce Pb toxicity by using them together in future research.

Biochar and Chitosan Regulate Antioxidant Defense and Methylglyoxal Detoxification Systems and Enhance Salt Tolerance in Jute (Corchorus olitorius L.)

“…The activities of MDHAR and DHAR were also augmented by BC addition in maize plants under water deficit [ 47 ]. The activity of DHAR was also enhanced in mung bean plants under Ni-induced oxidative stress [ 60 ], and similar results were also reported by Haider et al [ 62 ] in pea in lead (Pb)-stressed plants. Increased APX activity was also reported in salt-treated soybean plants following BC and CHT supplementation [ 11 ], in agreement with the present findings.…”

Effect of salt stress on the photosynthetic characteristics and endogenous hormones, and: A comprehensive evaluation of salt tolerance in Reaumuria soongorica seedlings

“…The content of Chl a and b and carotenoids in the leaves was assessed following the methods of 27 , and Brahmi et al 28 . For this purpose, 0.1 g of fresh leaf sample was homogenized in 20 mL of methanol, chloroform, and water (12:5:3).…”

Advances in the Research on Plant WRKY Transcription Factors Responsive to External Stresses

“…Of the other stresses that affect plants, oxidative stress is one of the most harmful [ 97 ]. In plants, the four major types of ROS are singlet oxygen (O 2 ), hydroxyl radicals (OH·), superoxide anions (O 2 − ), and hydrogen peroxide (H 2 O 2 ).…”

“…Thus, Zat12 plays an important role in the signal transduction network mediating the response of A. thaliana to oxidative stress. Specifically, Zat12 is required for the expression of Zat7 , WRKY25 , and Apx1 under oxidative stress conditions [ 97 ].…”