施氮对滴灌冬小麦花后光合生理、灌浆特性及产量品质的影响

为阐明黄淮海平原滴灌条件下施氮对不同高产冬小麦品种的调控机理,明确高产高效优质的施氮方式,以高产品种济麦22和烟农1212为试材,于2018—2020年2年间在大田滴灌条件下设置0,150,210,270 kg/hm² 4个施氮水平(济麦22用J0、J1、J2、J3;烟农1212用Y0、Y1、Y2、Y3),研究不同施氮量对滴灌冬小麦光合生理特性、籽粒灌浆特性、产量和品质的影响。结果表明：施氮可显著提高冬小麦上三叶的SPAD值,适量施氮显著提高了灌浆中后期的SPAD值和旗叶净光合速率(P_n),小麦旗叶SOD活性呈现单峰曲线的变化规律,各施氮处理的SOD活性均在花后14天达到最大值,N0处理的SOD活性在花后7天达到最大值,N2施氮水平下,2品种灌浆中后期旗叶SOD活性均最高。适量施氮能降低生育后期叶片膜脂过氧化程度,降低叶片MDA含量,使叶片功能期延长,从而提高生育后期的光合性能。随着施氮量的提高,2个品种的籽粒灌浆速率和最大理论千粒重均先增高后降低,不施氮处理下的T_m较各个施氮处理相对提前,济麦22的最大灌浆速率、最大理...

Effect of Nitrogen Application on Photosynthetic Physiology, Grain-Filling Characteristics and Yield and Quality After Anthesis of Winter Wheat Under Drip Irrigation

In order to study the high-yield, high-efficiency and high-quality nitrogen application rate under drip irrigation in the Huang-Huai-Hai Plain, a field trial was conducted using two high-yield varieties Jimai-22 and Yannong-1212 with 4 nitrogen levels, 0, 150, 210 and 270 kg/hm², under field drip irrigation during 2018-2020. The photosynthetic physiological characteristics, grain filling characteristics and grain yield were studied. The results showed that nitrogen application could significantly increase the SPAD value of the upper three leaves of winter wheat. Appropriate nitrogen application could significantly increase the relative chlorophyll content and flag leaf net photosynthetic rate (P_n) in the middle and late stages of grain filling. The SOD activity of wheat flag leaves showed a single peak curve. The SOD activity of each nitrogen treatment reached the maximum at 14 days after anthesis, and the SOD activity of N0 treatment reached the maximum at 7 days after anthesis. Under N2 nitrogen level, the flag leaf SOD activity of the two varieties was the highest in the middle and late filling stages. An appropriate rate of nitrogen application could reduce leaf membrane lipid peroxidation in late growth period and leaf MDA content, prolong leaf function period, and improve photosynthetic performance in late growth period. With the increases of nitrogen application rates, the grain filling rate and maximum theoretical 1000-grain weight of the two varieties increased first and then decreased. The Tm of the non-nitrogen treatments was relatively earlier than that of the various nitrogen treatments. For the maximum grain filling rate and maximum theoretical 1000-grain weight, Jimai-22 and Yannong-1212 appeared as the largest under N1 and N2 treatments, respectively. The yields of the two varieties first increased and then decreased with the increases of nitrogen application rates, and both were the largest at N2 treatment. The yield of Jimai-22 was higher than that of Yannong-1212 under N0 and N1 levels, but lower than that of Yannong-1212 under N2 and N3 levels, indicating that Yannong-1212 was more sensitive to nitrogen fertilizer and had a higher yield potential under high fertility and water conditions while Jimai 22 had a strong adaptability with a better performance under the low and medium fertilization. There were differences in the nitrogen responses on the yield components of the two varieties. The yield of Jimai-22 mainly depended on the number of ears and grains per ear, while the yield of Yannong-1212 was of a synergistic effect of the number of ears, grains per ear, and 1 000-grain weight. Nitrogen application significantly increased the protein, wet gluten, and sedimentation value of the two varieties. The quality of Yannong-1212 increased with the increases of nitrogen application in the range of 0~150 kg/hm², while Jimai-22 increased with the increases of nitrogen application in the range of 0~210 kg/hm². In summary, under this experimental conditions, the 210 kg/hm² of nitrogen applied under drip irrigation resulted in better photosynthetic characteristics, enzyme activity, grain filling characteristics, yield and quality of both cultivars and therefore should be the optimal nitrogen application rate.