冬春季夜间增温对小麦产量和氮素利用的影响
毕业论文关键词：小麦；夜间增温；氮素利用效率；硝酸还原酶；谷氨酰胺合成酶
Effects of winter and spring night warming on grain yield and nitrogen use efficiency of winter wheat (Triticum aestivum L.)
Abstract：To examine effects of night warming on grain yield and nitrogen use efficiency of winter wheat, field experiments were conducted using two winter wheat cultivars, Yangmai 13 (YM13) and Yannong19 (YN19), to investigate the effects of night warming during winter (Winter warming treatment, WT) and spring (Spring warming treatment, ST) and winter and spring (Winter and Spring warming treatment, WST) seasons on the grain yield, N assimilation, N accumulation and N utilization efficiency of winter wheat in the Yangtze River Basin of China in 2015-2016. The treatments of WT, ST and WST were designed from tillering to jointing, jointing to booting and tillering to booting with mean night temperature increased 1.47℃, 1.68℃ and 1.53℃, respectively. The results showed that WST treatment significantly increased grain yield, nitrogen agronomic efficiency and nitrogen recovery efficiency, the performance trend was WST > WT > ST > CK. The WST treatment significantly increased the nitrate reductase and glutamine synthetase activity of leaves therefore to increase nitrogen accumulation rate before anthesis and nitrogen accumulation amount at anthesis, while the WT and ST treatment had less impact than WST treatment. The WST treatment significantly increased nitrogen concentration of leaves at anthesis but had no effect on nitrogen concentration of spikes and stems, while the WT and ST treatment had less impact than WST treatment. Grain yield, nitrogen agronomic efficiency and nitrogen recovery efficiency were positively correlated with N accumulation from sowing to jointing and jointing to anthesis. These results indicate that night warming promotes pre-anthesis N assimilation and accumulation resulting in increased grain yield and nitrogen use efficiency, while winter night warming and spring night warming show less impact than winter and spring night warming.
Key words: Wheat; Night warming; Nitrogen use efficiency; Nitrate reductase; Glutamine synthetase
目 录
摘要2
关键词..2
Abstract2
Key words..3
引言3材料与方法4
1.1试验设计.4
1.2取样和测定方法.5
1.3计算方法.5
1.4数据分析.5
2结果与分析5
2.1产量和氮素利用率5
2.2生育时期、氮积累量和氮积累速率.6
2.3叶片NR和GS活性.7
2.4开花期小麦不同器官氮含量..8
2.5阶段性氮素积累与产量和氮效率的关系9
3讨论9
致谢.11
参考文献..11
冬春季夜间增温对小麦产量和氮素利用的影响
引言：
全球气候变暖已经成为一个全球性的问题[1]。联合国气候变化政府间专家委员会(IPCC) 在2014年的报告中指出：过去130年全球平均气温升高0.85(0.65℃-1.06℃)，本世纪末可能上升0.3℃-4.8 ℃[2]。全球气温在快速递升的同时，也表现出明显的非对称性，即冬春季的增温高于夏秋季，夜间增温高于白天[3-4]。温度作为作物生长发育中必不可少的非生物因子，未来气温的非对称性变化对作物生长将产生重要的影响。小麦是世界上种植面积最大的粮食作物之一，在中国仅次于水稻，玉米，是最重要的粮食作物之一。余卫东等的研究表明，施用氮肥可以提高小麦产量和品质[5]，氮肥的充足可以保障小麦的高产及高品质[6]。但是，小麦的氮素利用率低是一个全球性问题，中国的小麦氮素利用率远远低于世界的平均水平[7-9]。小麦氮素利用率低下，在造成农民种植成本增加的同时，多余的氮素盈余会通过水体，土壤等多种途径，成为水体污染和大气污染的重要来源，严重影响环境[10-11]。因此，研究冬春季夜间增温对小麦氮素利用的影响，对于在未来气候条件下提高小麦氮素利用效率具有重要的实际意义。硝酸还原酶和谷氨酰胺合成酶是极为重要的氮同化酶，对植物氮吸收能力改善有重要意义[12-16]。在旱生作物生长系统中，NH4+容易转化成NO3-，NO3-在被小麦吸收后，会在硝酸还原酶（NR）的作用下，转化成NO2-，NO2-会在亚硝酸还原酶（NiR）和谷氨酰胺合成酶（GS）的共同作用下转化成氨基酸[17]，因此，硝酸还原酶和谷氨酰胺合成酶是氮素同化过程中的重要酶。NR作为植物氮同化中最重要的限速酶，可以将吸收的硝态氮（NO3-）逐渐还原为亚硝态氮（NO2-），最终经过谷氨酸循环途径转化成可供植物利用的谷氨酰胺[17]。NR通过还原硝酸盐，进而调节氮代谢并最终影响到光合碳代谢。1974年，研究发现一条新的NH4+途径，即GS/GOGAT。在同化NH4+时，GS和GOGAT是同时起作用的[18]。NH4+进入该途径首先由GS催化合成谷氨酰胺，然后由GOGAT将谷氨酰胺和a-戊二酸转变为2个分子谷氨酸，其中一个分子谷氨酸可作为GS的底物，另一个分子谷氨酸可用于合成蛋白质、核酸等含氮化合物[18]。然而，目前对于增温对小麦氮素利用率的影响还未见有报道。因此，本次实验的目的明确：冬春季夜间增温对小麦氮素利用效率的影响及其生理机制。