Phosphorus Reduces Aluminum Toxicity in Oil Tea Roots by Regulating the Cell Wall Components and Antioxidant Defense System

Abstract

Aluminum (Al) toxicity is one of the most important impeding factors for plant growth and productivity in acidic soils. Phosphorus (P) application may alleviate Al stress in many plants. In this study we investigated the effect of P on Al toxicity in cell wall components and oxidative stress and to explore the underlying mechanisms in oil tea (Camellia oleifera Abel.) roots. Results indicated that Al toxicity severely inhibited root elongation, changed cell wall components, and caused oxidative damage to the roots of oil tea. However, P supply reduced the adsorption of Al in the cell wall by decreasing the demethylesterfied pectin content and hemicellulose 1 content that decreased the Al binding sites. Moreover, the addition of Palleviated the inhibition of xyloglucan endotransglucosylase and endo-β-1,4-glucanases activities under Al stress, which enhanced the loosening of the cell wall. P addition reduced the activities of polyphenol oxidase and phenylalanine ammonia lyase and enhanced the activities of reactive oxygen species scavenging enzymes, which reduced the oxidative damage caused by Al toxicity. The results reveal important mechanisms of P-induced mitigation of Al stress in oil tea roots that might be useful in the cultivation of plants on acidic soils.© 2021 Friends Science Publishers