CAJ | 학술논문

为了探讨不同水氮耦合处理对水稻根系形态生理、产量及氮肥利用率的影响，以徐稻3号为材料，进行防雨棚池栽试验，设置浅水层灌溉、轻度水分胁迫（?20 kPa）和重度水分胁迫（?40 kPa）3种灌溉方式及不施氮肥，中氮（normal nitrogen, MN,240 kg/hm2）和高氮（high nitrogen, HN,360 kg/hm2）3种氮水平，研究不同水氮耦合对根系形态、根系吸收面积、根系氧化力、根系氮代谢酶活性的影响。结果表明：灌溉方式与施氮量存在明显的互作效应，轻度水分胁迫增加了主要生育期根长、根质量、根质量密度、根系氧化力、总吸收面积、活跃吸收面积及根系氮代谢酶活性，降低穗分化后水稻根冠比，且与MN耦合后产量及氮肥农学利用率最高，为该试验最佳的水氮耦合运筹模式；重度水分胁迫则降低根长、根质量、根系活力及氮代谢酶活性，增加主要生育期根冠比。相关分析表明：幼穗分化始期至成熟期根冠比与水稻籽粒产量呈负相关关系，而其他根系形态、根系氧化力及氮代谢酶活性均与产量呈显著（P<0.05）或极显著（P<0.01）的正相关；根系质量、根质量密度及根冠比与氮肥农学利用率呈负相关，而穗分化至成熟期根系活跃吸收面积及穗分化至抽穗期根系氧化力均与氮肥农学利用率呈显著（P<0.05）或极显著（P<0.01）的正相关。表明通过适宜的水氮耦合调控，创造良好的根系形态、提高根系活力和氮代谢酶活性，将更有利于提高产量及氮肥利用效率。该研究对认识水氮耦合下根系形态生理差异、指导水稻高产高效栽培实践提供理论依据。
위료탐토불동수담우합처리대수도근계형태생리、산량급담비이용솔적영향，이서도3호위재료，진행방우붕지재시험，설치천수층관개、경도수분협박（?20 kPa）화중도수분협박（?40 kPa）3충관개방식급불시담비，중담（normal nitrogen, MN,240 kg/hm2）화고담（high nitrogen, HN,360 kg/hm2）3충담수평，연구불동수담우합대근계형태、근계흡수면적、근계양화력、근계담대사매활성적영향。결과표명：관개방식여시담량존재명현적호작효응，경도수분협박증가료주요생육기근장、근질량、근질량밀도、근계양화력、총흡수면적、활약흡수면적급근계담대사매활성，강저수분화후수도근관비，차여MN우합후산량급담비농학이용솔최고，위해시험최가적수담우합운주모식；중도수분협박칙강저근장、근질량、근계활력급담대사매활성，증가주요생육기근관비。상관분석표명：유수분화시기지성숙기근관비여수도자립산량정부상관관계，이기타근계형태、근계양화력급담대사매활성균여산량정현저（P<0.05）혹겁현저（P<0.01）적정상관；근계질량、근질량밀도급근관비여담비농학이용솔정부상관，이수분화지성숙기근계활약흡수면적급수분화지추수기근계양화력균여담비농학이용솔정현저（P<0.05）혹겁현저（P<0.01）적정상관。표명통과괄의적수담우합조공，창조량호적근계형태、제고근계활력화담대사매활성，장경유리우제고산량급담비이용효솔。해연구대인식수담우합하근계형태생리차이、지도수도고산고효재배실천제공이론의거。
Soil moisture and nitrogen (N) nutrient are the principal factors affecting rice production. Elucidation of their influences and coupling effects on grain yield of rice (Oryza sativa L.) would have great significance for high yielding and high efficiency of rice. As early as in 1911, Montgomery had began to study the effects of soil fertility on water consumption of maize in Mabraka, and Painten and Leamer noted that higher yield was obtained by applying more fertilizer under the condition of higher soil water potential in 1953. Domestic and foreign scholars have conducted extensive researches on the interaction of water and fertilizer. The existed researches focused on crop growth development, photosynthetic characteristics, yield and quality formation, nutrient and water use efficiency and other aspects of the studies, but most researches focused on the ground, few papers for the root characteristics, and the conclusions were not consistent. The purposes of this study were to investigate the effects of water and N coupling on root morphology and physiology, grain yield and N fertilizer use efficiency. A mid-seasonjaponica rice cultivar of Xudao 3 was planted. Three treatments of different N levels, i.e. no N fertilizer application, normal N (MN, 240 kg/km2) and high N (HN, 360 kg/hm2) and 3 irrigation regimes, i.e. submerged irrigation (0 kPa), alternate wetting and moderate drying (-20 kPa) and alternate wetting and severe drying (-40 kPa) were conducted. The results showed that there was a significant interaction between irrigation regimes and N applications, while not significant between the years for the main indices. In the same N condition, grain yield increased under the mild water stress, yet decreased significantly under the condition of alternate wetting and severe drying, an average reduction of 29.8%. When compared with no N fertilizer, rice yield of MN and HN treatment improved by from 54.0% to 60.6% (submerged irrigation), from 57.0% to 66.4% (-20 kPa) and from 33.0% to 61.0% (-40 kPa), and the result indicated that the application of N fertilizer could enhance rice yield significantly. Compared with the MN, grain yield under the condition of HN treatment was reduced, but the difference was not significant, except while water stress was severe, the yield of HN decreased significantly (P<0.05). High N fertilizer application had aggravated the soil drought, and reduced the effect of fertilizer regulation. The grain yield was the highest under the interaction of MN and mild water stress through the analysis of coupling effect of water and N, and the reason was it improved the filled grain rate and the 1000-grain weight when compared with other treatments. Under mild drying condition, root length, root dry weight, root activity, total root absorbing area, activity absorbing area and N metabolism enzyme activity at main growth stages were increased, but root-shoot ratio was decreased after panicle initiation stage. Mild water stress and MN enhanced rice yield and N use efficiency, being the best mode in this paper referred as the water-nitrogen coupling management mode.The opposite result was observed under the condition of alternate wetting and severe drying. Correlation analysis showed that grain yield was positively correlated to all the above morphological and physiological indices at main growth stages with the exception of negative correlation of the root-shoot ratio at the stage of heading.A negative correlation was observed between the N agronomy efficiency and the root dry weight, dry weight density, root-shoot ratio, while there was significant or extremely significant positive correlation between root active absorbing area, root activity at heading stage and N agronomy efficiency. These results suggest a good root morphology can increase root activity and N metabolism enzyme activity through the regulation of water and N, and will be much more beneficial to increasing grain yield and N use efficiency in rice production.