Dose-dependent suppression of photosynthetic pigments in maize (Zea mays L.) seedlings exposed to aflatoxin B1

Abstract:

Maize (Zea mays L.) is a key cereal crop in Northern India, yet its early growth can be compromised in aflatoxin-prone agroclimates where Aspergillus-associated contamination is frequent. The present study evaluated the phytotoxic influence of aflatoxin B1 on major photosynthetic pigments in maize seedlings under controlled conditions. Uniform seeds were exposed to five aflatoxin B1 concentrations (100, 250, 500, 1000, and 2000 µg/L) and germinated for ten days; pigment contents were quantified from newly emerged leaves using standard spectrophotometric methods. Aflatoxin B1 caused a clear, concentration-dependent decline in chlorophyll a, chlorophyll b, total chlorophyll, and carotenoids relative to the untreated control. At 2000 µg/L, chlorophyll a decreased by 70.15%, chlorophyll b by 64.29%, total chlorophyll by 68.60%, and carotenoids by 76.19%. Intermediate doses produced graded inhibition, confirming a strong dose–response relationship. The magnitude of carotenoid depletion suggests pronounced impairment of photoprotective capacity, which may aggravate photo-oxidative stress and reduce overall photosynthetic competence during the seedling stage. These results demonstrate that aflatoxin B1 toxicity extends beyond food and feed safety concerns to direct physiological disruption in maize, with likely implications for seedling vigor and stand establishment in contaminated regions such as Bihar. The findings support the urgency of adopting integrated mitigation strategies including improved storage, fungal management, and resistant cultivars to minimize mycotoxin exposure in maize-based production systems.