【作者】 张亚丽；

【导师】 沈其荣；

【作者基本信息】 南京农业大学 ， 植物营养学， 2006， 博士

【摘要】 水稻是我国最重要的粮食作物，生产了中国44％的粮食。为减轻人口增加对粮食需求的压力，我国一直将提高水稻单位面积产量作为水稻生产的主要任务。但是，我国水稻高产大多以基于施用过量的化学肥料来获得。目前中国稻田单季水稻氮肥用量平均为180kg ha^-1，这一用量比世界稻田氮肥单位面积平均用量大约高75％左右，部分地区的施氮量为270-300kg ha^-1，高的已达350kg ha^-1。随着水稻产量水平的提高，化肥特别是氮肥的施用量不断增加，对环境造成的压力也逐步加大。水稻对氮素的吸收和利用是农业生态系统中氮素循环的两个重要过程。充分挖掘作物吸收利用氮素的遗传潜力，从而在一定的氮肥投入下获得较高的产量，并减少氮素在土壤中的残留，是提高氮肥利用率的重要途径之一。而遗传改良的先决条件是了解控制作物高效吸收利用氮素的关键生理过程。近年来的研究发现，水稻氮素利用效率存在着基因型差异，因此有可能通过品种选育来获得氮高效的水稻品种，也就是从品种改良的途径来提高水稻氮素或氮肥利用率。水稻的氮高效包括植物体对氮素的高效吸收、氮素在植物体内的合理分配和高效利用、使水稻保持最大光合势和碳同化的适量氮素，从而获得较高的生物产量和经济产量。 本项目拟在田间条件下研究不同基因型水稻氮效率的差异，从中筛选出氮效率差异大的水稻基因型；在此基础上研究不同氮效率基因型水稻对氮素的吸收和生理利用过程，阐明水稻氮高效形成机理；丰富水稻氮营养理论，提出氮高效基因型水稻的形态与生理特征，为氮高效水稻品种的选育提供理论依据。田间试验包括三部分：2003年在南京农业大学江浦试验站在两个氮水平(0和180kg ha^-1)下进行了177个粳稻的氮效率基因型评价，从中选出氮效率差异较大的水稻基因型作为以后的供试材料；2004年继续在南京市江宁秣陵镇实施田间试验，在7个氮水平下(0-360kg ha^-1)研究了三个氮高效水稻基因型（武运粳7号、南光和4007）和一个氮低效基因型（ELIO）的产量及其构成、氮素吸收转运和干物质积累转运，阐明其与氮吸收和利用效率相关的关键过程；2004年在南京农业大学江浦试验站和江宁秣陵镇同时实施两个田间试验，在3个氮水平下(0、120和240kg ha^-1)研究了一个氮高效水稻南光和一个氮低效水稻ELIO在不同生育期的根系形态特征和生理特性，阐明与氮高效有关的根系形态特征和生理活性。 主要结果如下： 1．采用177个粳稻基因型在2个施氮水平下进行田间筛选试验来评价水稻的产量、吸氮量和氮素利用效率的变异情况。结果表明，随着供氮水平的增加水稻的产量更多还原

【Abstract】 China accounts for 20% of the total production of rice （Oryza Sativa L.） in the world but accounts for 37% of total nitrogen （N） fertilizers consumed in rice production. The primary reason for so much N fertilizer use in rice production is the very high grain yield goal of Chinese farmers. The average rice grain yield in China is 6180 kg ha^-1, which is 65% higher than the world average (3750 kg ha^-1). Another reason why N fertilizer use is so high for rice production in China is that rice farmers currently have smaller land holdings than previous and want to ensure their rice crops always have a sufficient supply of N. This results in excessive N applications and the risk in negative environmental effects. Such practices have aroused concerns of societies both in China and abroad. Nitrogen uptake and utilization of crop are two important parts in N cycle of Agriculture and ecology. The efficiency of the N use by rice is central to its overall yield potential and environment effect, and efforts to improve N use efficiency （NUE） must be guided by a through understanding of the processes that govern NUE. Breeding selection of high N efficient cultivars is an effective way to increase N fertilizer efficiency and reduce N loss in arable fields. Nevertheless, the agronomic basis underlining it is still quite vague.In this study, three parts of field experiments were conducted: （1） Field screening experiment for high and low NUE in Jiangpu Farm, 60 km northwest of Nanjing Agricultural University in 2003. Total 177 Japonica rice cultivars （71 medium-duration cultivars and 106 long-duration cultivars） were grown and supplied with two N application rates (0 and 180 kg ha^-1). The experiment was arranged as split plots in a randomized complete-block design with three replications. Nitrogen application rates were the main plots, and rice cultivars were the subplots. （2） Field experiment at Jiangning Farm, 40 km south of Nanjing Agricultural University in 2004. The field experiment was conducted with seven N rates (0, 60, 120, 180, 240, 300, and 360 kg ha^-1) as main plots and four Japonica rice cultivars selected from above field screening experiment as subplots in three replications. The four cultivars belonged to long-duration Japonica rice with similar growth duration and plant height were Wuyunjing 7, Nanguang, and 4007 classified as high NUE更多还原