在水培条件下 ,设计 0、1 4、2 8、42 mg/kg4个供氮浓度 ,研究其对扬稻 6号不同生育时期、生育阶段根系生长的影响。结果表明 :1依对氮素反应而言 ,根系性状可分为 3大类 :第 1类为随供氮浓度的提高而增加的性状 ,如每株不定根数 ;第 2类为随供氮浓度的提高而显著下降的性状 ,包括每条不定根长、不定根粗、不定根重和单位长度不定根重等 ;第 3类根系性状 ,在一定的氮素供应范围内 ,其生长量随供氮浓度的提高而增加 ,但供氮浓度进一步增加其增幅变小 ,如每株根干重和不定根总长度。2抽穗期根系性状中 ,每株不定根数主要取决于无效分蘖期 ,其次是有效分蘖期 ,再次为拔节长穗期 ;每株根干重和不定根总长度主要取决于无效分蘖期 ,其次是拔节长穗期 ,再次为有效分蘖期。3无效分蘖期是影响每株根干重、不定根数和不定根总长度生长的主要生育阶段 ,根系增加量的不同是由其生长速率不同所致 Under hydroponic conditions, four nitrogen concentrations of 0, 1, 4, 28, 42 mg / kg were designed to study their effects on root growth at different growth stages and growth stages of Yangdao 6. The results showed as follows: 1 According to the nitrogen response, the root traits can be divided into three major categories: the first is the increase with the increase of nitrogen supply, such as adventitious roots per plant; the second is with nitrogen concentration Including root length, adventitious root weight, adventitious root weight per unit length and adventitious root weight per unit length. In the third type of root traits, with the increase of nitrogen supply, But increased with a further increase of nitrogen concentration, such as the dry weight per root and the total length of adventitious roots. In the root traits at heading stage, the number of adventitious roots per plant mainly depends on the ineffective tillering stage, followed by the effective tillering stage and again at the jointing and panicle stage. The total dry root weight and adventitious root length per plant mainly depend on the inefficient tillering stage, The long panicle, once again effective tillering stage. 3 ineffective tillering stage is the main growth stage affecting root dry weight, adventitious root number and total length of adventitious roots. The difference of the increment of root system is caused by the different growth rate