Response Of Winter Wheat Genotypes With Different Phosphorus Efficiency To Phosphorus Supply During Seedling And Its Mechanism

The responses of winter wheat genotypes with different phosphorus efficiency (Xiaoyan 54 and Jing 411) and other genetypes to various phosphorus supply (phosphorus sufficiency, phosphorus removal, phosphorus fertilizers and phosphorus deficiency) were investigated in the nutrient solution and the soil pot experiment under the controlled conditions. The main results of the research are as follows:1. There was a significant difference in root morphological features, plant growth, phosphorus uptake and utilization between Xiaoyan 54 and Jing 411 under phosphorus sufficiency and phosphorus removal conditions in the nutrient solution under the controlled conditions. Compared with Jing 411, Xiaoyan54 had greater root/shoot ratio and perfect root parameters, such as smaller root radius; longer root length which might contribute to the efficient phosphorus uptake and utilization, resulting in higher phosphorus content in root, phosphorus uptake per unit root weight and per unit root length, root and shoot ratio, phosphorus adsorption rate, and phosphorus utilization.Both the phosphorus uptake per unit root length and per unit root weight could be used to express the phosphorus uptake of the wheat root, however, the much better linear correlation between phosphorus uptake and root length was found than that between phosphorus uptake and root weight. A much better correlation was also found between root absorbing area and root fresh weight than root dry weight, therefore, the phosphorus uptake on the base of root fresh weight expressed the genotypic difference between wheat genotypes more significantly.The phosphorus removal from the solution has significant constraint to the wheat growth, especially to the shoot growth of the two genotypes, and Jing 411 was more sensitive to phosphorus removal from the solution than Xiaoyan 54, and its shoot and root day weight decreased by 15.3%～54.9% and 5.3%～38.4% respectively during the three weeks of phosphorus removal, which were significantly higher than those of Xiaoyan 54 with the corresponding figures of 5.3%～41.2% and 3.3%～25.1%. The phosphorus removal from the solution increased the root/shoot ratio and the increment of Xiaoyan 54 was much more than that of Jing411, the tillers of the two genotypes were decreased by the phosphorus removal and Jing411 was far more sensitive to the removal.The phosphorus removal from the solution decreased the phosphorus content in plant, phosphorus uptake and phosphorus uptake rate of the two genotypes significantly, but the tolerance to the phosphorus removal of Xiaoyan54 was much stronger than Jing411.2. The effects of different phosphorus fertilizers (super phosphate SSP and calcium magnesium phosphate CMP) and two activators for CMP (inorganic activator IA and organic activator OA) on growth and phosphorus efficiency and genotypic difference of wheat genotypes with different phosphorus efficiency were investigated in the soil pot experiment under the controlled conditions. The results showed that there was no significant difference between SSP and CMP on growth of wheat genotypes...