籼稻品种的氮素累积量与根系性状的关系

2001和2002年，在群体水培条件下，分别以国内外不同年代育成的籼稻代表品种88个和122个为材料，测定植株的干物重、全氮含量以及13个有关根系性状，采用组内最小平方和的动态聚类方法对供试籼稻品种成熟期的氮素累积量进行聚类，分析不同氮素累积量类型籼稻品种根系有关性状的差异以及影响籼稻品种氮素累积量的主要根系性状。结果表明：(1) 供试籼稻品种成熟期氮素累积量差异很大，2001年A、B、C、D、E、F类籼稻品种的氮素累积量分别为10.40、13.47、16.17、18.50、20.72、25.13 g·m^-2，2002年分别为8.53、12.44、15.80、19.87、25.15、33.31 g·m^-2，类型间的差异均达显著水平；（2）全生育期天数和每日氮素吸收量对品种成熟期氮素累积量均有显著影响（R² = 0.960～0.996），并且后者显著大于前者；（3）成熟期氮素累积量与单株不定根数、单株根干重、单株不定根总长、单株根系总吸收面积、单株根系活跃吸收面积、单株根系α-NA氧化量等全株根系性状关系密切，与单条不定根长、单条不定根粗、单条不定根重等单条不定根性状和单位干重根系总吸收面积、单位干重根系活跃吸收面积等单位干重根系活性指标关系不密切；（4）多元逐步回归分析表明，单株根干重、冠根比、单株不定根数和单株不定根总长是影响籼稻品种氮素累积量的主要根系性状（R²=0.429～0.591）。

Relationship between N Accumulation and Root Traits in Conventional Indica Rice Varieties (Oryza sativa L.)

It is important in the long term to explore and exploit the potential of plant traits contributing to the nitrogen (N) absorption efficiency of rice. Root is primary organ for rice to explore and utilize N nutrient. However, little knowledge is known about the relationship between N accumulation and rice root traits. A solution culture experiment was conducted in 2001 and 2002, using eighty eight and one hundred and twenty two conventional indica rice varieties, respectively. A total of 13 traits responsible for morphology and physiological activity of rice roots was measured at heading stage while dry matter accumulation and N accumulation were determined both at heading and maturity. The tested rice varieties were classified into 6 types based on their N accumulation at maturity by the MinSSw method, and the differences of root traits between the types were analyzed to investigate the main root traits that significantly affected the N accumulation level. The average N accumulation of different types of rice varieties varied significantly, from 10.40 to 25.13 g·m^-2 in 2001, and from 8.53 to 33.31 g·m^-2 in 2002, respectively. Both whole growth duration and N uptake per day significantly affected N accumulation at maturity with the determinant coefficient ranged from 0.960 to 0.996, and the latter was more important than the former. N accumulation was closely correlated to number of adventitious roots per plant, root dry weight per plant, total length of adventitious roots per plant, total root absorption area per plant, root active absorption area per plant and total α-NA oxidizing amount of roots per plant, other than the traits for single adventitious root or root activity per unit dry weight. Polynomial stepwise regression analysis showed that N accumulation at maturity was significantly influenced by root dry weight per plant, ratio of shoot to root, number of adventitious roots per plant and total length of adventitious roots per plant (R²＝0.429－0.591). Morphological and physiological evidence in this study provided some prospects for improvement of root traits to improve N accumulation in indica rice.