Antioxidant System and Biomolecules Alteration in Pisum sativum under Heavy Metal Stress and Possible Alleviation by 5-Aminolevulinic Acid

Abstract

Environmental pollution is the most serious problem that affects crop productivity worldwide. Pisum sativum is a leguminous plant that is cultivated on a large scale in the Nile Delta of Egypt as a winter crop, and many of the cultivated fields irrigated with drainage water that contained many pollutants including heavy metals. The present research aimed to investigate the impact of Cd and Ni on the biochemical and physiological processes in P. sativum and evaluate the potential alleviation of their toxicity by 5-aminolevulinic acid (ALA). Seedlings of P. sativum were grown in Hoagland solution treated with CdCl2 or NiCl2 for 72 h in the growth chamber. Hydrogen peroxide, lipid peroxidation, protein carbonylation, reduced glutathione, oxidized glutathione, proline, phenolics, antioxidant enzymes, as well as Cd and Ni concentrations were measured at 0, 12, 24, 36, 48, 72 h. An experiment of alleviation was conducted where ALA was added to the growth solution at a concentration of 200 µM coupled with 100 µM of either CdCl2 or NiCl2. Hydrogen peroxide, lipid peroxidation, protein carbonylation, reduced glutathione, oxidized glutathione, proline, and phenolics were induced due to the toxicity of Cd and Ni. The activities of antioxidant enzymes [NADH-oxidase (EC: 1.6.3.1), ascorbate peroxidase (EC: 1.11.1.11), glutathione reductase (EC: 1.6.4.2), superoxide dismutase (EC: 1.15.1.1), and catalase (EC: 1.11.1.6)] were induced under the treatments of both metals. On the other hand, the soluble protein decreased gradually depending upon the time of exposure to the heavy metals. The concentration of Cd and Ni in the leaves treated plants increased in time of exposure dependent manner, while their contents remained within the acceptable limits. The addition of ALA decreased the oxidative stress in treated P. sativum plants. The results revealed the significance of using ALA in the cultivation of P. sativum might improve its tolerance against heavy metal stress.

Reactive Oxygen Species and Antioxidant Defense in Plants under Abiotic Stress: Revisiting the Crucial Role of a Universal Defense Regulator

“…A remarkable increase in lipid peroxidation along with the higher accumulation of H 2 O 2 was observed in O. sativa seedlings grown under nickel (Ni; 0.25 and 0.5 mM NiSO 4 , 72 h) toxicity [ 98 ]. El-Amier et al [ 99 ] also reported similar results with lower levels of Ni (100 µM Ni as NiCl 2 ) in Pisum sativum . On the other hand, cadmium (Cd) stress has been shown to increase MDA, H 2 O 2 , and O 2 •– levels in different crops [ 100 , 101 , 102 ].…”

Long-Term Effect of Heavy Metal–Polluted Wastewater Irrigation on Physiological and Ecological Parameters of Salicornia europaea L.

“…The Cd may bind to the carbohydrates of cell walls and the thiol groups of enzymes that exchanges metal ion concentrations such as Mg, Zn, and Fe (Iannelli et al 2002). Proline increases the tolerance of plants to heavy metals through metal chelation in the cytoplasm (Zengin and Kirbag 2007), scavenging hydroxyl radicals (Xing et al 2010), inhibit lipid peroxidation (Li et al 2013), maintaining the water balance (Mallick 2004), and the protection and stabilization of protein synthesis (El-Amier et al 2019). According to Tripathi and Gaur (2004), proline reduced the uptake of Cu by plant cells, and probably stabilized the plasma membrane, thus mitigating the toxic effects of Cu to the plant.…”

Regulation of ROS Metabolism in Plants under Environmental Stress: A Review of Recent Experimental Evidence

“…Metals/metalloids toxicity interrupts not only morpho-physiological traits but also causes enhanced oxidative stress resulting from lack of balance between antioxidant defense system and ROS production [ 83 , 84 , 85 , 86 , 87 , 88 , 89 ]. El-Amier et al [ 90 ] reported increased levels of LPO and H 2 O 2 accumulation in Ni (100 µM) stressed Pisum sativum L. seedlings. Such increments of oxidative stress indicators was even higher in the same crop with the same concentration of Cd as well.…”