Aluminium (Al) toxicity is one of the major sources of environmental stress that limit plant growth and productivity in many acidic soils, especially in the tropics and sub-tropics. Al toxicity subsequently leads to food insecurity in developing countries, especially in sub-Saharan Africa. Though plants can synthesize their antioxidants; the need exists to investigate whether under Al toxicity-induced stress; beta-carotene (β-Carotene) supplementation could ameliorate the stress situation and

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... hance growth and productivity. A 3× 10− 2 mM aluminium chloride (AlCl3) at pH 4.6 was used to stress plants. β-Carotene was extracted from carrots and high-performance liquid chromatography (HPLC) was used to determine its peak absorbance at 295 nm. β-Carotene's activity was determined using the thiobarbituric acid method. The effects of 50 and 200 µM concentrations of β-Carotene on the hydroponic growth of Amaranthus hybridus, subjected to Al stress, were evaluated in this study. Pre- and post- β-Carotene treatments were applied to A. hybridus seedlings before and after Al treatment for 72 h. Results showed that post- β-Carotene treatments significantly ameliorated plants from Al stress when compared to pre- β-Carotene treatments. Higher doses of β-Carotene significantly increased leaf number, plant height, length and number of inflorescence, fresh and dry weights of shoot, root and inflorescence but significantly decreased root length. The present study suggests that plants of A. hybridus were susceptible to Al toxicity-induced stress and post-β-Carotene supplementation could significantly ameliorate the stress situation and enhance growth and productivity. However, intrinsic antioxidants could be adequate for plants not subjected to stress.