缺磷胁迫对大豆根瘤生长和结瘤固氮的影响

采用砂培培养方法研究了缺磷胁迫对大豆根瘤生长和结瘤固氮的影响.结果表明:缺磷胁迫抑制了大豆根瘤的生长,表现为根瘤干重重下降,根瘤数量减少;缺磷胁迫显著降低了大豆的固氮能力,表现为根瘤吲氮酶活性和豆血红蛋白含量降低;缺磷胁迫降低了大豆的固氮量,固氮量随磷水平的增加而增加,随着生育时期的推进,固氮量表现为先增加后降低再增加的趋势,无磷(0μmol·L~(-1))与高磷(50 μmo·L~(-1))以及低磷(30μmol·L~(-1))与高磷处理间均达到了5%的显著差异.因此,缺磷胁迫抑制了大豆的结瘤固氮作用,使大豆的同氮效率降低.

Nodule Growth, Nodulation and Nitrogen Fixation in Soy bean (Glycine Max L.) as Affected by P Deficiency Stress

Phosphorus deficiency stress is a serious problem in the soil,how to resolve the problem of crop production reduction resulted from P deficiency is becoming global hot research. In this paper,a sand experiment was conducted to study the effects of P deficiency stress on nodule growth, nodulation and nitrogen fixation in soybean ( Glycine max L. ) at glassroom condition. The results showed that P deficiency restrained nodule growth which embody in nodule dry weight declined and nodule number decreased than that of normal P supplying,meanwhile,P deficiency significantly decreased nitrogen fixation capacity of soybean which embody in nodule nitrogenase activity and leghemoglobin concentration remarkably decreased than that of normal P supplying. P deficiency reduced nitrogen fixation quantity which increased with phosphorus concentration, and the trend was rising first and then declining, finally going up with the growing stages of soybean. There is significant difference between no P(0 mol· L~(-1) )and high P(50 mol·L~(-1) ) treatment,and low P and high P(30 mol·L~(-1)) treatment (P<5% ). Therefore,P deficiency restrained nitrogen fixation in soybean and then made the efficiency of nitrogen fixation declined.