The Biobrio 12(3&4), 2025

Effect of arsenic stress on growth parameters and antioxidant responses (proline and ascorbic acid) in maize cultivars.

Piyush Kumar & Preety Prasad

ABSTRACT:

Arsenic (As) is a naturally occurring metalloid that poses significant environmental and agricultural challenges due to its widespread contamination in soils and water sources worldwide. Contamination of soil by arsenic arises from both natural geological sources and anthropogenic activities, such as mining, industrial processes, and the extensive use of arseniccontaining pesticides and fertilizers. Among staple crops, maize (Zea mays L.) is critically important globally for food security, animal feed, and industrial uses, making the study of arsenic accumulation in maize tissues vital for understanding potential risks to human and animal health. Arsenic uptake by plants is complex, influenced by the arsenic species present in the soil (mainly arsenate (AsV) and arsenite (AsIII)) and the plant's physiological and biochemical mechanisms. The study aimed to explore the inherent genetic variability among the genotypes and their physiological and biochemical adaptations when exposed to arsenic stress at concentrations (0,50, and 100 mg/kg). Conversely, there was a substantial increase in oxidative stress indicators and antioxidant enzyme activities. Specifically, the levels of Proline and hydrogen peroxide (H2O2) increased, indicating enhanced lipid peroxidation and oxidative damage. In response to this stress, plants upregulated their antioxidant defense mechanisms, as observed by elevated activities of enzymes such as superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), and increased ascorbic acid (ASA) levels. Among the varieties, Pusa HM-9 exhibited the highest tolerance to arsenic stress. This variety showed minimal reduction in growth and chlorophyll levels compared to the others, suggesting better adaptability and efficient stress mitigation mechanisms. The toxic impact of arsenic on maize extends beyond accumulation, adversely affecting plant growth, seed germination, root development, and photosynthesis, while inducing antioxidative responses such as proline and ascorbic acid accumulation. Understanding these biochemical responses is essential for evaluating maize tolerance mechanisms and food safety in arsenic-contaminated environments.

Keywords:    

Arsenic, Maize, Ascorbic Acid, Proline

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