氮素对不同基因型紫玉米光合特性及氮素利用效率的影响
Effects of Nitrogen on Photosynthetic Characteristics and Nitrogen Utilization Efficiency of Different Purple Corn Hybrids

以3个不同血缘的紫玉米杂交组合ZS15、FS11和68G1为供试材料进行大田试验，研究不同氮肥水平［不施氮肥（N0）和施纯N 225 kg/hm（N225）］对不同基因型紫玉米光合特性及氮素利用效率的影响。结果表明：与N0处理相比，N225处理下紫玉米单株叶片的净光合速率(Pn)、叶面指数（LAI）、SPAD值、最大光化学效率（Fv/Fm）、PSⅡ活性（Fv/Fo）、叶片氮质量分数分别较N0处理平均提高9.21%、7.51%、3.78%、1.94%、13.72%、5.75%，且不同基因型紫玉米光合特性对氮肥反应不同。相关分析表明，开花期紫玉米穗上叶和穗位叶的SPAD值与叶片含氮量呈极显著正相关，紫玉米氮素利用效率和产量分别与开花期、灌浆期、成熟期的SPAD值呈极显著正相关，相关系数分别为0.853、0.860、0.973与0.819、0.827、0.985。紫玉米氮素利用效率和产量与开花期的Pn呈极显著正相关，相关系数分别为0.999和0.994。LAI差异不是紫玉米氮素利用效率和产量差异的原因。紫玉米叶片的叶绿素Fv/Fm与氮素利用效率和产量呈显著负相关，相关系数分别为-0.502和-0.554。
A field experiment was carried out to study the effects of nitrogen on photosynthetic characteristics and nitrogen utilization efficiency of different purple corn hybrids including ZS15, FS11 and 68G1 under low N level (0 kg/hm2) and high N level (225 kg/hm2).The result indicated that the net photosynthetic rate, LAI, SPAD, Fv/Fm, Fv/Fo and leaf nitrogen content under N225 level were 9.21%, 7.51%, 3.78%, 1.94%, 13.72%, and 5.75% higher than the counterparts under N0, respectively.The photosynthetic characteristics of materials were different in response to nitrogen treatments.The correlation analysis indicated that the SPAD of upper ear leaf and ear leaf had significantly positively correlation with leaf nitrogen content at anthesis stage.The nitrogen utilization efficiency and yield had significantly positively correlation with SPAD at the stage of anthesis, seed-filling and maturity and the correlation coefficients were 0.853, 0.860, 0.973, 0.819, 0.827, and 0.985, respectively.The nitrogen utilization efficiency and yield had significantly positively correlation with net photosynthetic rate at anthesis stage with the correlation coefficients of 0.999 and 0.994 respectively.Difference of LAI was not the main reason for the differences of nitrogen utilization efficiency and yield of purple corn.The Fv/Fm had significantly negative correlation with nitrogen utilization efficiency and yield of purple corn and the correlation coefficients were -0.502 and -0.554 respectively.