通过2年田间试验,对过度绿熟品种CD30和中度绿熟品种ZH505,在无氮肥(N1)和225kgN/hm² 的HN4Cl(N2)、KNO3(N3)、尿素(N4)、猪粪(N5)处理下的田间产量及产量构成因子、吸氮量、氮素收获指数、保绿度等进行方差分析,测定了吐丝期(0DAS)及吐丝后20天(20 DAS),40天(40DAS)和成熟期叶片氮浓度,以及0DAS、20DAS和40DAS穗位叶中叶绿素a(Chl a)、叶绿素b(Chl b)、核酮糖-1,5-二磷酸羧化酶/加氧酶(Rubisco)、磷酸烯醇式丙酮酸羧化酶(PEPC)的含量变化。结果表明,氮肥形态显著影响玉米产量和氮素收获指数,其中产量变化为N4>N3> N2>N5>N1,氮素收获指数变化为N5>N2> N3>N4>N1；品种间的产量和吸氮量没有显著差异,但ZH505的氮素收获指数显著高于CD30,而CD30的保绿度显著高于ZH505；叶片氮浓度在20DAS达到最高值,其中在N1和N5处理下,ZH505叶片氮浓度降低时间早于CD30,但是CD30叶片残留氮浓度高于ZH505；氮肥形态和品种显著影响Chl a和Chl b的变化,其中N4处理下Chl a和Chl b含量最高,且显著高于N5处理；而品种CD30的Chl a和Chl b含量显著高于ZH505,在40DAS差异最为显著,两个品种在40DAS的Chl a和Chl b平均含量较20DAS分别降低19.11%、13.63%和42.98%、36.31%；氮肥形态显著影响Rubisco和PEPC的变化,其中N5显著高于N4。因此根据玉米品种持绿特性,通过尿素和有机肥配合施用,提高叶片光合氮素利用效率,是实现玉米高产氮高效的一种途径。

In the field experiments of two years, maize cultivars of CD30 (over stay-green) and ZH505(mediate stay-green) were tested in the Southwest China. We evaluated the yield, the ear characteristics, the nitrogen accumulation, the nitrogen harvested index (NHI), the stay-green degree, the dynamic changes of leaf nitrogen concentration (at the silking stage, 20, or 40 days after silking, and at the maturity stage) from silking to maturity, the chlorophyll a (Chl a) value, the chlorophyll b (Chl b) value, ribulose-1,5-bisphosphatecarboxylase/oxygenase (Rubisco) value, the phosphoenolpyruvateScarboxylase (PEPC) value (at the silking stage, 20, and 40 days after silking) with five nitrogen treatments (0 kg N/hm_²HN₄Cl 225kgN/hm_², KNO₃ 225kgN/hm_²,Urea 225kgN/hm_², and manure 225 kg N/hm_²). We found that, the form of nitrogen fertilizer significantly affects maize yield and NHI, the yield is urea treatment>KNO₃treatment>HN₄Cltreatment> organic fertilizer treatment> N0 treatment, and the NHI is organic fertilizer treatment>HN₄Cl treatment>KNO₃ treatment> urea treatment> N0 treatment. There was no significant difference in the yield and N accumulation of the two maize varieties, but the NHI of ZH505 was higher than that of CD30, and the stay-green degree of CD30 was higher than that of ZH505.The leaf N concentration reached the highest value at 20DAS. Among them, under the organic fertilizer and N0 treatments, the leaf nitrogen concentration of variety ZH505 decreased earlier than CD30, but the residual nitrogen concentration of CD30 leaves is higher than that of ZH505 at maturity. The N form and variety significantly affect the value of Chl a and Chl b. The content of Chl a and Chl b were the highest under urea treatment, and was significantly higher than that of organic fertilizer treatment. The concentration of Chl a and Chl b in ZH505 was significantly higher than that of ZH505, and the difference was most significant at 40 DAS. The average concentration of chl a and chl b of the two cultivars at 40DAS was reduced by 19.11%, 13.63% and 42.98% ,36.31%respectively compared with 20DAS. The form of N significantly affects the changes of Rubisco, and PEPC, and the organic fertilizer treatment is significantly higher than that of urea treatment. So, according to the trait of stay green, the combined application of urea and organic fertilizer is a way to achieve high yield and high nutrient efficiency of maize.

国家自然科学基金(41907080)、四川省科技计划(2016JY0012,2020YFH0171),四川省农业科学院前沿学科研究基金(2019QYXK022)和人才基金(2020BJRC005)。