旱地双垄沟播春玉米氮代谢及其高效利用调控机制研究

The technique of double ridges and planting in furrows effectively regulates water, fertilizer and calories of soil, but the fertilizer use efficiency is low and instability, the metabolism of triple coordinated regulation was not well understood. Therefore, in order to improve the fertilizer use efficiency, we will clear the physiological and molecular mechanism of nitrogen metabolism, and investigate the water, fertilizer and calories of soil effects with the technique of full film mulching on double ridges and planting in furrows. The research material is the spring corn. We will study (1) the key enzyme of nitrogen metabolism in major organ during growth and development stage with double ridges cultivation techniques, (2) gene expression of the key enzyme of nitrogen metabolism in major organ during growth and development stage with different cultivation techniques, (3) the extraneous nitrogen forms and levels to effect the nitrogen metabolism and utilization ratio, (4) the correlated relationship between the key enzyme activities, gene expression of nitrogen metabolism and the nitrogen levels, nitrogen forms and utilization effectiveness. We will illuminate the mechanism about the nitrogen metabolism and efficient utilization for the double ridges and planting in furrows of maize. Through the intensive theoretical study on the nitrogen metabolism, the project can provide the useful theoretical basis on the high production of the spring corn in arid and semi-arid regions.

旱地全膜双垄沟播技术能够有效调控土壤水、肥、热，但该技术下肥料的利用效率仍低而不稳，对土壤水、肥、热协同调控的机制研究尚未深入。因此，明确氮代谢的生理及分子机制，探明全膜双垄沟播技术下土壤水、肥、热效应，是有效提高肥料利用效率的重要途径。本项目以春玉米为试材，将研究：（1）全膜双垄沟播玉米氮代谢的关键生育时期、代谢器官和酶；（2）不同栽培方式下玉米氮代谢关键酶及其基因表达，氮素吸收、同化及转运，土壤温度及水分动态变化；（3）影响玉米氮代谢及其高效利用的外源氮素形态及施用水平；（4）氮代谢关键酶及其基因表达与氮素水平、形态配比及其利用效率的相关关系。旨在阐明旱地双垄沟播春玉米氮代谢及其高效利用的调控机制。项目成果将对氮代谢理论的深入研究，推动干旱半干旱地区春玉米高产高效提供理论依据。

玉米是我国旱农地区主要的粮食作物，对社会经济的可持续性发展具有重要作用。氮素形态供应状况和栽培模式是影响作物生长及产量形成的重要因素。全膜双垄沟播技术作为旱农地区主要的玉米栽培模式，增产效果显著，种植面积连年增加。本项目通过研究全膜双垄沟播和全膜平铺穴播栽培模式下不同形态氮素配比对玉米生长发育、氮代谢关键酶活性及其产物和产量的影响，研究发现全膜双垄沟播较全膜平铺穴播显著提高了玉米前期土壤温度， 0-200cm土层平均土壤含水量提高2.77%。硝铵态氮配施较单一氮素土壤平均含水量平均增加1.86%。全膜双垄沟播较全膜平铺穴播玉米株高、茎粗显著增加，叶面积指数和总光合势分别提高2.86%~27.27%和7.86%~14.47%。硝铵比为3:1较其它配比总光合势提高2.29%~15.17%。全膜双垄沟播和两种形态氮素配施均增加了玉米叶绿素SPADE值和干物质量，干物质量增加6.53%~30.56%。硝铵比为3:1的营养器官干物质转运量增加7.36%~46.27%；对籽粒贡献率平均增加11.3%。与全膜平铺穴播相比，全膜双垄沟播显著提高了玉米氮代谢关键酶（NR、NiR、GS、GOGAT）活性。两种氮素配施较单一氮素提高了氮代谢关键酶活性；硝铵比为3:1时效果最佳。全膜双垄沟播、两种形态氮素配施均提高了玉米叶片可溶性蛋白和游离氨基酸含量。两种形氮素配施下可溶性蛋白和游离氨基酸含量随硝态氮比的增高而增加，当硝铵比为3: 1时效果最佳。全膜平铺穴播较全膜双垄沟播显著抑制了玉米氮素积累，降低了茎叶中氮素对籽粒的贡献率，平均降低8.20%。硝铵氮配施促进了氮素吸收，提高硝态氮比例有利于提高茎叶对籽粒氮素的贡献率，硝铵氮配比为1:1和3:1时均可提高氮肥偏生产力。其中3:1配比的氮素吸收效率最高，比其它配比平均增加11.45%。相比全膜平铺穴播，全膜双垄沟播增加了玉米穗长、穗粗、穗行数及百粒重，产量显著提高3.67%~15.84%。两种氮素配施较单一氮素处理玉米产量、收获指数和WUE显著提高，硝铵比为1:1和3:1的增幅达4.86%~29.57%。