施氮量对不同氮效率玉米品种根系时空分布及氮素吸收的调控

马存金; 刘鹏; 赵秉强; 张善平; 冯海娟; 赵杰; 杨今胜; 董树亭; 张吉旺; 赵斌

doi:10.11674/zwyf.2014.0406

施氮量对不同氮效率玉米品种根系时空分布及氮素吸收的调控

Regulation of nitrogen application rate on temporal and spatial distribution of roots and nitrogen uptake in different N use efficiency maize cultivars

摘要

摘要: 【目的】研究不同氮效率夏玉米根系的时空分布、植株氮素吸收利用特性及其对氮素用量的响应，探讨玉米氮素高效利用的生理基础，以期探明通过采用氮高效品种、促进根土互作、提高根系与水肥时空耦合、提高玉米氮素利用效率，强化环境友好型生产的有效途径。【方法】试验于2011-2012年在山东农业大学黄淮海玉米技术创新中心（N3618，E11712）和作物生物学国家重点实验室进行，以氮高效玉米品种郑单958（ZD958）和氮低效品种玉米秀青73-1（XQ73-1）为试验材料，在大田条件下设置两个氮素水平（0和315 kg/hm2），采用土壤剖面取样法和系统取样法分别进行根系相关指标、干物质及氮素积累与分配的测定。【结果】ZD958整个生育期根系相关指标（根系干重、根长密度、根系TTC还原量、根系吸收面积及活跃吸收面积）及其在深层土壤（60-100 cm）中所占的比例、单株生物量、单株绿叶面积、植株氮素积累量、单株籽粒产量均显著高于XQ73-1（P0.05），抽雄期和完熟期根系干重、根长密度、根系TTC还原量、根系吸收面积、根系活跃吸收面积、单株绿叶面积分别比XQ73-1高12.02%、 8.39%、 25.34%、 34.48%、 29.22%、 7.76%和36.74%、 24.21%、 36.29%、 29.94%、 32.83%、 13.73%，完熟期单株生物量、植株氮素积累量、籽粒产量分别比XQ73-1高11.65%、 11.78%、 15.16%。施氮后两品种各指标均显著提高，ZD958和XQ73-1根系干重、根长密度、根系TTC还原量、根系吸收面积、根系活跃吸收面积、单株绿叶面积抽雄期分别提高8.13%、 6.12%、 18.08%、 15.10%、 24.71%、 12.06%和7.19%、 4.59%、 10.47%、 10.82%、 13.02%、 7.15%，而完熟期分别提高16.48%、 22.43%、 19.26%、 15.03%、 27.45%、 14.97%和15.02%、 14.59%、 13.01%、 12.81%、 21.95%、 11.06%；单株生物量、植株氮素积累量、单株籽粒产量完熟期分别提高9.40%、 10.08%、 13.43%和5.20%、 8.56%、 9.69%。相关分析表明，植株吸氮量与根长密度、根系干重、根系活跃吸收面积呈显著线性正相关（相关系数均在0.8以上）。 ZD958花前根系对氮素的响应度高于XQ73-1，花后则低于XQ73-1。【结论】氮高效玉米品种ZD958根系总量大、深层土壤根系多、根系活力高、氮素吸收能力强；施氮条件下优势更加明显，对ZD958作用大于XQ73-1，说明氮高效玉米品种发达且分布合理的根系保证了植株对氮素的吸收，有利于进行光合生产、获得较高籽粒产量。两品种对氮素的响应不同，氮高效品种花前对氮素的响应度高于氮低效品种，花后则相反。因此，可过适度减少氮高效品种花前施氮量、增加花后施氮量，而适度增加氮低效品种花前施氮量、降低花后施氮量来促进根系发育，提高氮素利用效率。

Abstract: 【Objectives】The ascertain of the physiological mechanism of nitrogen nutrition of a maize cultivar is the base of choosing nitrogen high efficient cultivar with reasonable and effective temporal and spatial coupling distribution. Therefore, the development and function of root, the relationship between temporal and spatial distribution characteristics of roots and the nitrogen uptake were studied. 【Methods】Split plot experiments were conducted in 20112012 at the Technological Innovation Center of Maize in Huang-Huai-Hai Region (N3618, E11712) and the State Key Laboratory of Crop Biology, located at Shandong Agriculture University in Taian. One high efficiency cultivar (ZD958) and one low efficiency cultivar (XQ73-1) were used and two nitrogen levels: 0 and 315 kg/ha, were designed. The temporal and spatial distribution characteristics of roots in the soil profile were investigated systematically and the nitrogen uptake of summer maize in different growth stages was analyzed and the accumulation amount of dry matter was calculated.【Results】All the terms investigated are significantly higher in ZD958 than in XQ73-1 throughout the whole growth stage (P0.05). The total root dry weight, root length density, root TTC reducing quantity, root absorbing area, root active absorbing area and leaf area of ZD958 are 12.02%, 8.39%, 25.34%, 34.48%, 29.22%, 7.76% and 36.74%, 24.21%, 36.29%, 29.94%, 32.83%, 13.73% higher than those of XQ73-1 at tasseling stage and fully ripening stage, respectively. The biomass, N accumulation amount, grain yield per plant of ZD958 are 11.65%, 11.78% and 15.16% higher than those of XQ73-1 at fully ripening stage, respectively. The values of all the tested terms are increased significantly due to the application of nitrogen fertilizer. Compared with corresponding N0(no N application), the total root dry weight, root length density, root TTC reducing quantity, root absorbing area, root active absorbing area, leaf area increased by 8.13%, 6.12%, 18.08%, 15.10%, 24.71%, 12.06% in ZD958 and 7.19%, 4.59%, 10.47%, 10.82%, 13.02%, 7.15% in XQ73-1 at tasseling stage, but 16.48%, 22.43%, 19.26%, 15.03%, 27.45%, 14.97% in ZD958 and 15.02%, 14.59%, 13.01%, 12.81%, 21.95%, 11.06% in XQ73-1 at fully ripening stage. The biomass, N accumulation amount, grain yield per plant were increased by 9.40%, 10.08%, 13.43% inZD958 and 5.20%, 8.56%, 9.69% in XQ73-1 at fully ripening stage. Significant positive linear correlation exists between the amount of N-uptake and the root length density, root dry weight and root active absorbing area with correlation coefficient of higher than 0.8 at all the items. The responses of root index of the two cultivars to nitrogen are different, higher response of root index in ZD958 than in XQ73-1 before anthesis stage, but lower after that. 【Conclusions】High N efficiency cultivar has larger root number and root density in deeper soil layers, more rational root distribution than low nitrogen efficiency cultivar, leading to stronger nitrogen uptake ability. Application of N intensifies the differences between the two genotype cultivars. The superiorities in root development in high nitrogen efficiency cultivar ensure the effective nitrogen uptake, delay of leaf senescence, the accumulation of dry matter, and finally higher grain yield.

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