尿素酶抑制剂NBPT对大豆根系的影响

Effect of Urease Inhibitor NBPT on Growth of Soybean Roots

大豆根系特别是与大豆共生的根瘤菌对土壤中的NH4+非常敏感,尿素酶抑制剂NBPT能够抑制土壤尿素酶的活性并减缓NH4+的水解速率已得到广泛的认同。为探索利用NBPT提高大豆生长发育的途径,对施用NBPT的大豆,利用氧化还原法,乙炔还原法和凯氏定氮法分别测定了大豆根系活性,根瘤固氮活性和植株含氮量,并测定了大豆根瘤的数量和重量。结果表明,NBPT提高了大豆整个生长期的根系活力,对根瘤固氮酶活性有促进作用,根瘤数量和重量都有增加,因而大豆植株的含氮量也随之增加,根系生长得到促进。NBPT作为氮素由于施用量小对大豆根系及根瘤的作用有限。

Soybean roots and particular the symbiosis root nodules are vulnerable to the NH4 and NHs in the soil. NBPT as soil urease inhibitor has been known to inhibit the urease activity in the soil and therefore deduce the hydrolysis velocity of urea. The purpose of this study was to find a way to increase soybean growth using NBPT. In this study, NBPT mixed proportionally with urea and NBPT without urea were applied to the soybean plants to analyze the effect of NBPT on the soybean root growth in root vigor, root nodule number and weight, and the activity of nitrogen fixation of root nodule. Results showed that NBPT mixed proportionally with urea increased the soybean root vigor, root nodule number and weight, the root nitrogen （N） fixation activity,and therefore the root growth was increased by a high content of N in the soybean plant. NBPT as a fertilizer applied was beneficial to soybean root growth. However,the effect of NBPT used as a fertilizer for N was limited.