对大田条件下玉米品种’掖单13’(Zea mays ‘Yedan13’)和’’丹玉13’(Z. mays ’Danyu13’)初生根(包括初生胚根和次生胚根)和不同层次次生根的直径及其中的N、P、K、Ca和Mg含量进行了比较分析。分析结果表明,’掖单13’和’丹玉13’初生根直径总体上小于次生根;从第1层至第7层次生根,基本上为发生时间越晚,根直径越大;而2个品种第7层至第9层次生根基部直径的变化趋势有一定的差异。’掖单13’和’丹玉13’初生根和不同层次次生根中N、P、K、Ca和Mg含量差异显著(P<0.05);’掖单13’初生根中的N、P、K、Ca和Mg含量分别为27.36、3.75、14.34、10.19和5.94g·kg^-1,不同层次次生根中的N、P、K、Ca和Mg含量分别为4.31～8.99、0.91～1.29、4.07～15.27、2.35～5.42和1.52～4.06g·kg^-1; ‘丹玉13’初生根中的N、P、K、Ca和Mg含量分别为28.65、4.65、14.54、10.33和6.04g·kg^-1,不同层次次生根中的N、P、K、Ca和Mg含量分别为7.41～12.70、0.84～1.27、1.81～24.69、2.46～3.73和1.12～2.73g·kg^-1;2个品种初生根中N、P、Ca和Mg含量均最高,K含量也显著高于第1层至第7层次生根;总体上看,不同层次次生根中的N、Ca和Mg含量随发生时间的先后呈逐渐降低的趋势,P和K含量随发生时间的先后呈逐渐增加的趋势,但2个品种间有一定的差异。研究结果显示,次生根根直径的增大与其对地上部分的固持能力有关。 

The diameter and contents of  N, P, K, Ca and Mg in primary roots(including primary radicle and secondary radicle) and secondary roots from different layers of Zea mays `Yedan 13' and Z. mays  `Danyu 13' were compared and analyzed under the field condition. The analysis results show that the diameter of primary roots is smaller than that of secondary roots generally. The later the occurrence time, the bigger the diameter of secondary roots from the first to the seventh layer, but the changing trend of base diameter of secondary roots from the seventh to the ninth layer of two cultivars has a certain difference. The differences of contents of N, P, K, Ca and Mg in primary roots and secondary roots from different layers of Z. mays `Yedan 13' and Z. mays `Danyu 13' are significant (P< 0.05).The contents of N,  P,  K,  Ca and Mg in primary roots of Z. mays `Yedan 13' are  27.36, 3.75, 14.34, 10.19 and  5.94g·kg<sup>- 1</sup> and those in secondary roots from different layers are 4.31- 8.99, 0.91-1.29, 4.07- 15.27, 2.35- 5.42 and 1.52- 4.06g·kg<sup>- 1</sup>, respectively. The contents of N, P, K,  Ca and Mg in primary roots of Z. mays `Danyu 13' are  28.65, 4.65,  14.54,  10.33 and 6.04g·kg^{- 1}and those in secondary roots from different layers are 7.41- 12.70, 0.84- 1.27, 1.81- 24.69,2.46- 3.73and 1.12- 2.73g·kg^{- 1}, respectively. The contents of N, P, Ca and Mg in primary roots of two cultivars are the highest, and the content of K in primary roots is obviously higher than those in secondary roots from the first to the seventh layer. On the whole, as occurrence time delaying, N, Ca  and Mg contents in secondary roots from different layers decrease, and P and K contents in crease, but there is a certain difference between two cultivars. It is concluded that the increasing of secondary root diameter has a relationship with stability to above-ground part.