施氮对大豆根瘤生长和结瘤固氮的影响

Nodule Growth,Nodulation and Nitrogen Fixation in Soybean(Glycine max L.)as Affected by Nitrogen Application

采用框栽试验研究了施氮对大豆根瘤生长和结瘤固氮的影响,结果表明,施氮对大豆根瘤形成、生长和固氮能力有显著影响,随着N用量的增加,根瘤干质量、根瘤数量呈现先逐渐增加而后降低的趋势,而固氮酶活性和豆血红蛋白含量则表现为持续下降的趋势,适量施氮对根瘤生长有显著的促进作用,当氮素供应不足时则会抑制根瘤的生长,但当氮素供应过量时也会抑制根瘤的形成。从根瘤干质量和根瘤数量来看,各处理间表现为N100>N200>N50>N25>N0,以N100处理下根瘤干质量最大,根瘤数量最多,显著高于不施氮(N0)和其他施氮处理,从不同生育时期来看,根瘤干质量表现为从苗期到花期再到鼓粒期,大豆根瘤的数量呈现出先明显增加后逐渐减少的趋势,高峰出现在花期,而根瘤数量表现为花期>苗期。施氮显著抑制了固氮酶活性和豆血红蛋白含量,随施氮水平的增加,固氮酶活性和豆血红蛋白含量显著降低,表现为N0>N25>N50>N100>N200,表明施氮使大豆根瘤的固氮效率显著降低,因此,从大豆固氮效率来讲,施氮对大豆根瘤固氮具有抑制作用。方差分析结果表明,施氮和不施氮处理间均达到了5%的差异显著水平。因此,从大豆固氮和氮肥施用平衡的角度来看,应适量施用氮肥,既可以充分利用大豆的固氮功能,节约氮肥,又可以获得较高的产量。

In this paper, a pot experiment was conducted to study the effects of different nitrogen application on nodule growth, nodulation and nitrogen fixation in soybean（ Glycnie max L. ）. The results showed that nitrogen application affected nodule forming, growth and nitrogen fixation capacity significantly, nodule dry weight and nodule number showed a trend of increasing first and then declining, while nitrogenase activity and leghemoglobin concentration showed the trend of continuosly declining. Proper N application improved nodule growth, however N deficiency or excessive N use restrained nodule growth. There was an order of N100 〉 N200 〉 NS0 〉 N25 〉 NO for nodule dry weight and nodule number. At dif- ferent growth stages, nodule dry weight showed a trend of increasing first and then declining from seedling stage to podding stage, and for nodule number was flowering stage 〉 seedling stage. N application significantly decreased nitrogenase activi- ty and leghemoglobin concentration with N rates increasing, showed an order of NO 〉 N25 〉 NS0 〉 N100 〉 N200, suggest- ed that N application decreased the efficiency of nitrogen fixation. The difference analysis showed that there was a signifi- cant difference between N application （N25, NS0, N100 and N200） and no N （N0） treatment. Therefore, from the view of the balance between N fertilization and nitrogen fixation, proper N application not only makes the best of nitrogen fixation function which economizing N fertilizer application but also obtaining higher output of soybean.