Phosphorus Alleviates Aluminum Toxicity in Al-Sensitive Wheat Seedlings

The role of phosphorus (P) in the amelioration of aluminum (Al) toxicity to plants is still unclear. The aim of this study was to examine the amelioration of Al toxicity by Psupply. The study involved growing Al-sensitive wheat seedlings for 13 days in an acidic soil [pH 4.5 in calcium chloride (CaCl2)] with increasing added rates of P(0,20, 40, and 80 mg P kg(-1) soil) and Al [0, 50, and 150 mg aluminum chloride (AlCl3) kg(-1) soil]. The results indicated that the effects of Al toxicity in this soil could be fully alleviated by the application of P at 50 mg AlCl3 kg(-1). The 150 mg kg(-1) AlCl3 treatment significantly reduced root growth, but this was partially overcome by the 80 mg kg(-1) P treatment. High P significantly reduced the concentration of Al in the apoplast, root, and shoot. It is possible that an insoluble Al-P complex forms in the soil and this decreases Al bound in apoplast as well as uptake into the roots. High P decreased the translocation of Al from root to shoot. This study also concluded that detoxification of Al3+ by P mainly occurs in soil but not within the plant tissue.