施氮量对东北粳稻根系形态生理特征的影响

 以东北粳稻牡丹江27和牡丹江31为试验材料，研究了不同氮肥水平对东北粳稻根系形态和生理特性的影响。结果表明，在同一生育时期，随着氮肥用量的增加，水稻根数、根长、根粗、根体积和根干质量等指标也有所提高，根系的总吸收面积均也有所增加。三种氮肥水平下地上部干质量均随生育进程急剧增加，两品种的根干质量在孕穗期和抽穗期达最大值，抽穗期后根冠比降低，而地上部干物质量增大，单株根系伤流强度都随着抽穗后时间的推移先升高后降低，两品种根系α 萘胺氧化力分别在抽穗期和乳熟期达最大值，且根系氧化力在各时期的变幅随施氮量的提高逐渐变小。水稻在孕穗期的根数、根长、根粗、根干质量和根冠比与产量之间的相关性达到显著水平，各生育期根系的总吸收面积和比表面积均与产量呈正相关，且在乳熟期时相关系数最大。

Influence of Nitrogen Levels on Morphological and Physiological Characteristics of Root System in japonica Rice in Northeast China

The morphological and physiological characteristics of root system were studied with the Northeast japonica  rice Mudanjiang 27 and Mudanjiang 31 as experimental materials under different nitrogen  levels. The results showed that  with rising  nitrogen level, the number, length, thickness, volume, dry weight and total absorption area of root increased  at growth stage. Shoot dry weight increased dramatically with growth stages under three  nitrogen application levels, root dry weight of Mudanjiang 27 and Mudanjiang 31 maximized  at booting stage and heading stage, respectively. After heading stage, root shoot ratio reduced, while shoot dry weight increased. Root bleeding intensity  per plant increased firstly and then decreased after heading stage under three levels of nitrogen application. The α NA oxidizing ability of two varieties  maximized at  heading stage and milk ripe stage, respectively.   The  root oxidizing ability for both varieties  in the whole growth duration fluctuated within a narrowing band  with  increasing  nitrogen application level. The correlation   between rice root number, root length, root diameter, root weight, root shoot ratio and yield became significant at the booting stage. The total absorption area,  ratio of surface area of root system and yield were positively correlated in the whole  growth  duration with  the correlation coefficient reaching a maximum  at  milk ripe stage.