Effect Of Zinc On Lens Culinaris.pdf

The excessive use of heavy metals is a major source of soil pollution, primarily due to anthropocentric activities such as mining, toxic waste disposal, and agricultural use of herbicides and pesticides. Certain oligo-elements, essential for plant growth, become toxic at high concentrations. Zinc (Zn) acts as a cofactor for several enzymes and is necessary for various physiological processes, but high concentrations of Zn and copper (Cu) can disrupt cellular processes, inducing phytotoxicity. When plants are exposed to high levels of heavy metals, reactive oxygen species (ROS) are induced, and plants activate ROS-scavenging mechanisms, including enzymatic and non-enzymatic systems. The main objective of this investigation was to study the effect of zinc on the growth, accumulation, and antioxidant responses of Lens culinaris legume. The seeds were germinated in a culture medium with different Zn concentrations, and the plant growth, malondialdehyde (MDA) level, and antioxidant enzymes activities were measured. The results showed that the growth of lentils is inversely proportional to the concentration of Zn in the culture medium, and the level of MDA becomes very important at 10,000 μM of Zn. The evaluation of enzymatic activities indicated that the decline of peroxidase (POD) is concomitant with the increase in glutathione peroxidase (GPx), and glutathione S-transferase (GST) and catalase (CAT) reach their maximum activities at 10,000 μM and 3,000 μM of Zn in upper parts and roots, respectively. These findings revealed that MDA is a real indicator of oxidative stress in Lens culinaris and that this plant is tolerant to the presence of Zn in the culture medium by developing a powerful antioxidant system, but beyond a certain concentration, its antioxidant system becomes ineffective, and the plant enters a stress state.