Abstract:A rhizobox experiment was carried out to study effects of various concentrations of phosphate (Pi) supply on root morphology, rhizosphere processes, and plant P uptake of two wheat genotypes (Shimai15 and Hengguan35). The results showed that Shimai 15 had more increases of shoot biomass and phosphorus(P) content with high Pi application compare with Hengguan 35.While the decreases of shoot biomass and P accumulation of Hengguan35 under limited Pi supply were much lower than those of Shimai 15, indicating Hengguan35 might have higher tolerance to low Pi stress than Simai15. Under the high Pi supply, the fine root length within ≤0.16 mm diameter and its percentage in total root length of Shimai 15 were greater than those of Hengguan35. Contrarily, without Pi fertilization, the total root length and the proportion of fine roots with diameter ≤ 0.16 mm in total roots of were larger in Hengguan 35 than Shimai 15. Under the high Pi supply, the higher soil organic P content and the lower soil microbial biomass P were in rhizosphere, while without Pi supply, the activity of soil alkaline phosphatase was higher and soil organic P content and soil pH were lower in rhizosphere. Compared with the optimum Pi supply, the high Pi supply increased soil pH and decreased the activity of alkaline phosphatase in rhizosphere. However, low Pi supply decreased soil pH in rhizosphere. It is suggested that the adaptations of plants on two fronts would occur when subjected to the low Pi stress. One is better root characteristics, such as longer roots, especially with more fine roots, which are important for plant to efficiently utilize soil Pi, and the other is the rhizosphere processes, such as soil acidification and the transformation of soil organic P to Pi, which help plant to acquire more Pi from rhizosphere soils and benefit plant’s tolerance to the low Pi stress. However, the changes of root morphology under high Pi supply may be associated with the wheat cultivars with different capacity of P uptake and P accumulation.