磷素营养与大豆生长和共生固氮的关系

在水培条件下，研究了磷素营养对２个大豆品种生长和共生固氮的影响。结果表明，水培液中磷含量在２．３～９．３ｍｇ／Ｌ时，２个大豆品种的植株生长量、根瘤数、根瘤干重、固氮活性和氮积累量均随磷浓度增加而显著增加；而在９．３～３７．０ｍｇ／Ｌ时则大大降低。磷浓度过高会造成毒害，但植株的磷积累量却与施磷量呈显著的线性回归关系。植株不同部位磷含量是根瘤＞根＞地上部分；氮含量是根瘤＞地上部＞根。２个大豆品种对磷肥反应有显著差异。

The Relation of Phosphorous Nutrition to Growth and Symbiotic Nitrogen Fixation of Soybean Cultivars

A water culture experiment was conducted to study the relation of phosphorous nutrition to soybean growth and its symbiotic nitrogen fixation.The results showed that shoot dry weights,nodule numbers,nodule dry weights and nitrogen fixation activities were evidently increased with the increase of phosphate fertilizer rates when phosphorus added to nutrient solution was below 9.3 mg/L,and greatly decreased when it was in the range of 9.3-37.0 mg/L.Excessive phosphorus in solution would bring about phosphorous toxicity to soybean plants.However,a significant linear regression was found between accumulative P amounts in the above ground plant and fertilizer P added.The phosphorus contents in different parts of plant were as follows:nodule >root>shoot;and the nitrogen contents were in the order:nodule>shoot>root.In additon,the two soybean cultivars had different response to phosphate fertilizer as shown in this experiment.