Author(s): Yuh Nien Chow, Lai Kuan Lee, Nor Azazi Zakaria, Keng Yuen Foo
Linked Author(s): Yuh Nien Chow
Keywords: Food security, lead, phytotoxicity, Vigna radiata, wastewater irrigation.
Abstract: Water pollution is the most alarming topic over the past several decades, with the leading cause of diseases and deaths of more than 14, 000 people per day. Today, wastewater irrigation has emerged to be a widespread strategy to fulfill the pressing need of non-conventional water resources. These discharges carry appreciable amount of toxic chemicals or trace elements, usually exceeding the maximum allowable limits, suggesting the possible risks to the food chain, water courses, and ecosystem. Heavy metals are among the most carcinogenic, teratogenic, mutagenic, and neurotoxic constituents accumulating in the irrigation water. Lead is one of the most abundant metal contaminant in aquatic and terrestrial ecosystems. Owing to its low solubility, mobility, and freedom from the microbial degradation in soils, it could accumulate in soil, and absorbed by plants to induce physiological and biochemical dysfunctions. Confirming the assertion, this study placed an early attempt to investigate the effects of lead-doped irrigation water on the physical, biochemical, and physiological responses of Vigna radiata seedlings. The seed germination, length of roots and shoots, proline accumulation, photosynthetic pigments, and antioxidative responses were elucidated. Results revealed that seed germination was unaffected, but the elongation of roots and shoots were hindered as a function of lead concentrations. Profound reductions were observed in chlorophyll-a, chlorophyll-b, and carotenoid content in the treated seedlings. The activities of proline, guaiacol peroxidase, catalase, and ascorbate peroxidase were altered, with a pronounce stimulation at 0. 55 mM of lead. The current findings shed light on the detrimental implications of wastewater irrigation practice on the physical growth, physiological and biochemical characteristics, and antioxidative systems of Vigna radiata seedlings. The health threats, toxicity, and injuries implications could be exacerbated on a larger scale by the indiscriminate application of low quality water resources as a technical solution to the scarcity of clean, fresh irrigation water
Year: 2017