摘要：
[目的]研究不同产量水平的大豆Glycine max(L.)Merr.品种生育后期根系伤流液中氮素等养分元素含量的变化规律,以期为大豆育种和高产栽培提供生理依据.[方法]以3种不同产量水平(低、中、高产)的大豆品种为试验材料,栽培管理条件相同,测定开花期(R2期)、结荚期(R4期)和鼓粒期(R6期)大豆根系伤流强度及伤流液中氮素(总氮、硝态氮、铵态氮和氨基酸)以及磷、钾、钙和钠等养分含量.[结果]整个生育后期高产大豆品种根系伤流强度、总氮、氨基酸含量明显高于中、低产品种,平均值分别高13.4%和24.0%、31.9%和74.2%、46.3%和81.0%.根系伤流液中硝态氮含量高于低产品种,平均值高19.9%;铵态氮含量低于低产品种,平均值低16.5%;根系养分元素磷、钾、钙含量均高于中、低产品种.不同产量水平的大豆品种伤流强度的最高值均出现在R4期,R4期籽粒产量与伤流强度呈极显著正相关(r=0.765**);根系伤流液中总氮和氨基酸含量在R2期达最高值,磷、钾在R4期含量最高.[结论]在开花期以后,高产大豆品种根系代谢旺盛,具有较强的吸收能力和活力,这可能是大豆高产的关键因素.%[Objective]To explore changes of nitrogen and nutrient element contents of root bleeding saps of soybeans [Glycine max (L.) Merr.] with different yield levels at late growth stages, and provide a physiological basis for soybean breeding and high-yielding cultivation.[Method]Soybean cultivars with three different yield levels (low-, middle- and high-yielding) were planted under the same cultivation condition. Root bleeding intensity, the contents of nitrogen compounds (total nitrogen, nitrate nitrogen, ammonium nitrogen and amino acids) and other nutrient elements (P, K, Ca and Na) in root bleeding saps of soybeans were measured at flowering (R2), podding (R4) and seed-filling (R6) stages respectively.[Result]Root bleeding intensities, total nitrogen and amino acid contents of high-yielding cultivars were 13.4% and 24.0%, 31.9% and 74.2%, 46.3%and 81.0% higher than those of middle- and low-yielding cultivars at late growth stages. Nitrate nitrogen content of high-yielding cultivar was 19.9% higher than that of low-yielding cultivar,while ammonium nitrogen content of high-yielding cultivar was 16.5% lower than that of low-yielding cultivar. The P, K and Ca contents of high-yielding cultivar were higher than those of low- and middle-yielding cultivars. The bleeding intensities of soybeans with different yield levels reached the maxinum values at R4 stage, and the grain yield was significantly positively correlated with bleeding intensity at R4 stage (r = 0.765**). The contents of total nitrogen and amino acid in root bleeding saps reached the maximum values at R2 stage while the contents of P and K were the highest at R4 stage.[Conclusion]Root metabolism of high-yielding cultivar was vigorous and had stronger absorption capacity and vitality, which might be the key factors to increase soybean yield.
