不同磷效率大豆品种光合特性的比较

以不同磷效率大豆品种为材料, 调查磷高效和磷低效品种的生理指标，测定大豆生育期地上器官干物重，分析光合特性及物质生产特性。结果表明，在低磷条件下, 各生育期的叶绿素含量、可溶性蛋白含量、净光合速率、气孔导度和叶肉导度均以磷高效品种较高, 磷高效品种光合作用较强，CO₂同化能力较高。各生育期, 供试品种的叶绿素含量、可溶性蛋白含量、净光合速率、气孔导度和叶肉导度均在结荚期达到高峰而后下降, 但磷高效品种下降速率低于磷低效品种。磷高效品种的单株和群体均具较高光合效率及生长参数, 并受磷浓度影响较小, 主要原因是其植株吸收磷量较多, 有利于植株体内磷素平衡, 即便在低磷条件下也有相对较强的光合能力，令其在低磷、中磷和高磷条件下都有较高的产量和籽粒磷效率。

Comparison of Photosynthetic Characteristics in Soybean Cultivars with Different Phosphorus Efficiencies

Soybean is sensitive to phosphorus deficiency in whole growth stage. Phosphorus plays an important role in photosynthesis. Our objective is to compare the difference of photosynthetic characteristics in soybean cultivars with different phosphorus efficiencies under different phosphorus levels in Shenyang during 2006–2007. The results showed that the soybean cultivars with high phosphorus efficiency had higher seed yields and higher seed phosphorus efficiency at each of the three phosphorus levels. Under phosphate deficiency condition, the cultivars with high phosphorus efficiency had a higher photosynthesis and CO₂ assimilation capacity, as well as higher soluble protein content, lower stomatae restriction and higher yield. The contents of chlorophyll, soluble protein, net photosynthetic rate, stomatal conductance and mesophyll conductance all reached the peak at the podding stage, and then descended. Growth rate, Leaf area duration (LAD) and net assimilation rate showed a rapid increase during the podding and grain- filling stages. The soybean cultivars with high phosphorus efficiency had higher net photosynthetic rate and growth indices at both the single plant and population levels, and had a small response to the change of phosphorus concentration. The main reason was that the phosphorus in the plants could be balanced by more absorption of phosphorus under low phosphorus situation, which could ensure a stronger photosynthesis.