Lead-induced Hormesis in Corchorus olitorius: Growth, Antioxidants and Micronutrients Accumulation

Kholoud Shaker

Abstract: Corchorus olitorius, a leafy vegetable with characteristically high content of minerals and antioxidants, is known for its ability to grow in Pb-contaminated soils with minimum influence on its morphological parameters. Its growth can be stimulated by low Pb concentrations, although Pb is not a nutritional element and is known for its toxicity to plants. This phenomenon is referred to as hormesis, the stimulatory impact of low doses of some toxins on the growth and metabolism of living organisms. Therefore, plants subjected to Pb contamination may have better crop yield despite of their potential negative influences when entering the food chain. In this study, Pb was added to the cultivated soil in concentrations that are within permissible levels for cultivated soils. Growth parameters significantly increased under Pb treatment. Hormesis in plants has been previously reported to be related mainly to growth parameters, pigments and antioxidants, all are tested in this work, in addition to the contents, accumulation and translocation factors of Pb as well as the essential micronutrients Fe, Zn, Cu and Ni. Antioxidants significantly decreased and the accumulation of some essential micronutrients as Fe and Zn is disturbed. The tested parameters were measured in two different plant life stages, early and late vegetative stages. The hormetic effect was more significant in older plants. Hormesis could be used as an agricultural practice for increasing crop productivity. However, the characteristic nutritional and medicinal value of this plant is negatively affected.

Keywords: Antioxidants; Corchorus olitorius; Hormesis; lead; micronutrients

Date published: 2022-10-11