Toxic Effects of Lead on the Growth & Metabolism of Sugarcane (Saccharum officinarum L.) Plants

Abstract

One well-known environmental pollutant that poses major risks to plant health is lead (Pb), especially in regions where industrial discharge, vehicle emissions, and the overuse of chemical pesticides and fertilizers are prevalent. Lead is a hazardous and non-essential heavy metal that is known to interfere with important plant physiological and biochemical functions. This study was designed to explore and quantify the impact of various concentrations of lead on growth & metabolic functions of sugarcane (Saccharum officinarum L.), a commercially significant crop cultivated extensively for sugar and ethanol production.Under regulated environmental circumstances, sugarcane plants were exposed to different concentrations of lead nitrate (0 ppm as control, 50 ppm, 100 ppm, and 200 ppm) as part of the experimental design. To evaluate growth inhibition, morphological characteristics including fresh weight, dried weight, root length, and plant height were assessed. To ascertain the degree of metabolic disruption brought on by Pb stress, important metabolic markers such as total soluble protein content, the activity of vital antioxidant enzymes like catalase (CAT) and peroxidase (POD), and chlorophyll pigments (chlorophyll a, chlorophyll b, and total chlorophyll) were also assessed.The results demonstrated a clear dose-dependent decline in all measured growth and biochemical parameters. Higher concentrations of lead resulted in marked reductions in plant height and biomass, reflecting the inhibition of cell division and elongation processes. A notable drop in chlorophyll content indicated compromised photosynthesis, most likely as a result of oxidative stress and chloroplast structural damage brought on by lead. Protein synthesis was also adversely affected, indicating disruptions in nitrogen metabolism and enzyme function. Furthermore, the activities of CAT and POD enzymes declined progressively with increasing Pb levels, revealing a compromised antioxidative defense mechanism in the plants.These findings confirm that lead toxicity severely impairs both the growth and metabolic performance of sugarcane plants. The study emphasizes the vulnerability of sugarcane to lead stress and draws attention to the potential decline in crop yield and quality in regions where soil & water are contaminated with heavy metals. Understanding these physiological and biochemical responses is essential for developing effective phytoremediation and soil management practices. The outcomes also highlight the urgent need for pollution control and sustainable agricultural strategies to protect valuable crops from environmental hazards and to ensure food security in affected ecosystems.