【作者】 吕小红；

【导师】 陈温福；

【作者基本信息】 沈阳农业大学 ， 作物学， 2011， 博士

【摘要】 我国水稻的平均氮肥利用效率为35%。氮肥利用率低不仅造成了资源的浪费,增加了生产成本,更重要的是会导致一系列环境和健康问题。因此,研究作物氮肥利用率及品种间氮肥利用存在差异的生理机制具有重要意义。本文以穗型直立的紧凑型品种沈农07425和穗型弯曲的松散型品种秋光为材料,研究了不同施氮条件下两种株型品种氮肥利用的差异及其生理基础,主要结果如下：1、不同株型品种间N2O排放通量差异显著,沈农07425的硝化-反硝化气体损失远小于秋光。不同株型品种N2O排放通量随施氮量的变化存在差异,沈农07425的N2O排放通量随着施氮量提高而增加,高氮处理下N2O排放通量最大；秋光的N2O排放通量则中氮处理下最大。品种与施氮水平的交互作用对N2O排放通量影响较大,与品种因素相比,N2O排放通量受施氮水平影响更大。2、不同株型品种间土壤硝化-反硝化细菌数量差异显著。紧凑型品种沈农07425与松散型品种秋光土壤的硝化细菌数量存在较大差异,沈农07425的硝化细菌数量大于秋光；反硝化细菌数量上,紧凑型沈农07425的中氮、高氮处理显著大于松散型秋光。不同株型品种硝化-反硝化细菌数量随施氮量的变化存在差异。紧凑型沈农07425的硝化细菌、反硝化细菌数量均随着施氮水平提高而相应增加。松散型秋光的硝化细菌数量随施氮水平提高而减少,以不施肥对照硝化细菌最多；反硝化细菌数量以不施肥对照最大,但符合高氮>中氮>低氮的规律。3、在一定范围内,施氮对两株型水稻品种的株高、分蘖数、叶绿素含量和单株叶面积均起促进作用,均随施氮水平的提高而增大。总根长在不同株型品种间差异显著。紧凑型沈农07425的总根长随施氮量增加而减少,而松散型秋光则在高氮条件下总根长最大。两品种的根干重、根体积表现一致,均随施氮水平的提高而增大。4、不同株型水稻的叶片NO3-含量、NO2-含量和NH4+含量、硝酸还原酶活性均随着外源氮素水平的升高而呈上升趋势。沈农07425和秋光的可溶性蛋白含量高氮处理明显高于中、低氮处理,脯氨酸含量、电导率和可溶性糖含量高氮、低氮处理显著大于中氮处理。两品种叶片丙二醛含量随着水稻的逐渐衰老而增加,各处理间低氮、高氮处理丙二醛含量大于中氮处理。叶片CAT、POD和SOD活性均呈现高氮>中氮>低氮的关系。5、两株型品种根系NO3-含量、NO2-含量、NH4+含量和硝酸还原酶活性均随着施氮量的增加而增加。齐穗期沈农07425根系NO3-含量与秋光的NO3-含量差异极显著。沈农07425根系NO2-含量拔节之后的增幅远小于秋光。NH4+含量随生育期的变化两品种间差异较大。紧凑型沈农07425与松散型秋光的根系总吸收面积、活跃吸收面积、根系氧化力随着供氮水平的增加而增大。6、紧凑型品种沈农07425在高氮处理下达到最大硝化强度,松散型品种秋光低氮处理下土壤硝化强度较大。两品种的土壤反硝化作用强度表现一致,随着施肥水平的提高土壤反硝化强度升高,受施氮水平影响更大。紧凑型品种沈农07425拔节期土壤的硝酸还原酶活性最大,秋光则分蘖期活性最大,品种间差异较大。两株型品种的土壤硝酸还原酶活性均随施氮水平提高而不断增强。各处理间土壤脲酶活性中氮处理高于低氮、高氮处理。紧凑型品种沈农07425土壤还原物质总量随施氮量的增加而增加；松散型品种秋光高氮处理的土壤还原物质总量明显低于中氮和低氮处理。沈农07425土壤活性还原物质含量随施氮量的提高而增加,而施氮量对松散型品种秋光的土壤活性还原物质含量影响不大。土壤全氮含量两品种间差异不显著,但随着施氮水平的提高,两株型水稻品种土壤全氮含量均不同程度增加。7、随着施氮量的提高,紧凑型品种沈农07425和松散型品种秋光的产量增加。氮肥对两株型品种有效穗数的影响均达显著水平,品种间差异极显著,有效穗数的大小次序为高氮>中氮>低氮。两株型品种间结实率差异达显著水平,每穗粒数、千粒重达到极显著水平。不同株型品种的氮肥利用率存在差异：沈农07425的氮素谷物生产效率遵循低氮>中氮>高氮的趋势,且各处理间差异显著。秋光中氮处理的氮素谷物生产效率显著大于低氮、高氮处理。氮收获指数、氮肥偏生产力两品种均符合低氮>中氮>高氮的关系。更多还原

【Abstract】 The average nitrogen use efficiency of rice is only 35% in China. The low nitrogen use efficiency not only result in the waste of resources, increased production costs, but also lead to a series of environmental and healthy problems. Therefore, studies on nitrogen use efficiency and the mechanism of the differences on nitrogen utilization of different varieties play an important role. The compact rice Shennong 07425 with erect panicle and the loose rice Akihikari with curved panicle were used to study the differences on nitrogen utilization and its physiological basis under several nitrogen levels in pot experiment. The main results are as follows.1. There is significant difference on N2O Flux between the tow varieties. The nitrification-denitrification gas loss in Shennong 07425 is far less than that of Akihikari. N2O Flux of different plant species changes with different nitrogen levels, the N2O Flux in Shennong 07425 increases with increasing nitrogen application, and it reaches the maximum under high nitrogen treatment. But Akihikari attains its maximum under middle nitrogen treatment. The interaction of variety and nitrogen level affect N2O Flux greatly, relatively speaking, N2O Flux is mostly decided by nitrogen level than variety.2. The number of nitrifying-denitrifying bacteria in soil is significantly different between the tow varieties. The number of nitrifying bacteria in the compact variety Shennong 07425 is much larger than that of Akihikari, but only the number of denitrifying bacteria under middle and high nitrogen treatment is significantly greater than the loose variety Akihikari.The number of Nitrifying-denitrifying bacteria of different plant species changes with different nitrogen levels. The number of Nitrifying-denitrifying bacteria in Shennong 07425 increases with increasing nitrogen application. It raises crosscurrent on the number of nitrifying bacteria in the loose variety Akihikari, the CK treatment attains the maximum. The CK treatment handles the largest number of denitrifying bacteria in Akihikari, and it still in line with high nitrogen> middle nitrogen> low nitrogen level.3. The increasing application of nitrogen fertilizer enhance plant height,number of tillers,chlorophyll content(SPAD value) and leaf area per plant within a certain range. Total length of root in Shennong 07425 decreases with nitrogen level raised, but it reaches the maximum in high N level in Akihikari. The total length is mainly affected by plant type.It appears similar result on dry weight and root volume between the two varieties, all magnify with increasing levels of nitrogen fertilizer.4. NO3- content, NO2- content, NH4+ content, nitrate reductase activity in leaves of both rice increases with elevated levels of nitrogen. Soluble protein content under the high nitrogen treatment reflects significantly higher than the middle and low nitrogen treatment of both. And the proline content, relative conductivity, soluble sugar content under High nitrogen, low nitrogen treatment show significantly greater than that in middle nitrogen level. MDA content in leaves of two varieties elevate with the gradual increase of aging, and it shows that MDA content among treatments for low nitrogen, high nitrogen are bigger than that in middle nitrogen level. The CAT activity, POD activity, SOD activity among these treatments reveal that high nitrogen is greater than middle nitrogen and middle nitrogen is larger than low nitrogen treatment.5. NO3- content, NO2- content, NH4+content, nitrate reductase activity in root of both rice increases with elevating levels of nitrogen. NO3- content of the two varieties appears extremely significant difference in the fullheading stage. The growth of NO2- content in Shennong07425 is smaller than Akihikari after jointing stage. The NH4+ content changes with the growth stage differently between the two varieties. Compact and loose Shennong 07425 total absorption area of root Akihikari active absorption area, root oxidation, reducing power as the nitrogen level increases. There is the same trend of root total absorption area, active absorption area, oxidizing ability per gram between Shennong 07425 and Akihikari:nitrogen level is bigger, the items become stronger.6. Nitrification intensity of soil in Shennong 07425 increases with nitrogen level, but it reaches the maximum in low nitrogen level in Akihikari. There is the same trend of denitrification intensity between Shennong 07425 and Akihikari:nitrogen level is bigger; the denitrification intensity became stronger. The denitrification intensity is chiefly decided by nitrogen level. The compact variety Shennong 07425 reaches the largest soil nitrate reductase activity in jointing stage, Akihikari is in tillering stage, and soil nitrate reductase activity has large difference between varieties. Soil nitrate reductase activity of two varieties increases with the growing nitrogen level. Urease activity under the middle nitrogen treatment reflects significantly higher than the high and low nitrogen treatment.Total reducing substances of Shennong 07425 increases with the growing nitrogen level. Total reducing substances of Akihikari under the high nitrogen treatment reflects significantly higher than the middle and low nitrogen treatment. The active reducing substances of Shennong 07425 get larger with the increasing nitrogen level, but nitrogen application has no obvious effect to active reducing substances of Akihikari. There is no significant difference of total nitrogen content between the two varieties. Total nitrogen content of two varieties increases to a certain extent with the growing nitrogen level.7. Grain yield of compact variety Shennong 07425 and loose variety Akihikari increases significantly with the growing nitrogen level. The panicles indicate significant difference between species, and it in line with high nitrogen> middle nitrogen> low nitrogen level. The full-grain percentage exposes significant difference between species, grain number of per ear and 1000-grain weight reveal extremely significant difference between the two species.Nitrogen grain production efficiency of Shennong 07425 follow the low nitrogen> middle nitrogen> high nitrogen trends, and it has significant differences among treatments. Nitrogen grain production efficiency of Akihikari under the middle nitrogen treatment reflects significantly higher than the high and low nitrogen treatment. Nitrogen harvest index and nitrogen partial factor productivity of two cultivars are in line with low nitrogen> middle nitrogen> high nitrogen.更多还原