Effect of Zinc on the Growth and the Antioxidant System of Lens Culinaris Cultivated on Agar Medium

Abstract

This study aimed to analyze the impact of Zn on the growth and the antioxidant response of Lens culinaris. For this purpose, the seeds were germinated for 6 days in an MS/2 culture medium with different Zn concentrations. Malondialdehyde (MDA), total protein contents, and antioxidant enzymes activities were measured in both parts of the plant by spectrometry. The results showed that from the Zn concentration of 250 μM, the growth of lentils is inversely proportional to the concentration of Zn in the culture medium. The variations in the level of MDA are not very significant, but at 10 000 μM of Zn in the medium, the level becomes very important, whilst the total protein content decreased. Besides, the evaluation of enzymatic activities indicated that the decline of peroxidase (POD) is concomitant with the increase in glutathione peroxidase (GPx) and that glutathione S-transferase (GST), as well as catalase (CAT) reach their maximum activities at 10 000 μM and 3000 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.