不同种植密度下东北春玉米根系特征及其干物质积累的差异比较

以郑单958和先玉335为供试品种,对45 000、67 500和90000株/hm2种植密度下春玉米关键生育期0～60 cm土体根系的主要形态指标及其干物质积累进行分析.结果表明,随密度提高,0～ 60 cm土体中玉米单株根系生物量积累下降,但群体根系总生物量呈上升趋势.3个密度下,从拔节期至乳熟阶段郑单958玉米根系的根长、根表面积、根体积与根长密度均随生育进程呈单峰曲线变化,在抽雄吐丝期达最大值；先玉335根系的相应形态指标从拔节期至乳熟阶段呈下降趋势,在拔节期最大.抽雄吐丝期和乳熟期,两个品种的单株根长、根表面积和根体积随密度增加而下降,但群体的总根长、根表面积、根体积和根长密度随密度的增加而增大.

Differential Comparison of Root Morphology and Matter Accumulation of Spring Maize under Different Plant Densities in Northeast China

With the aid of field experiment site of Gongzhuling city, Jilin Province, the study of maize (Zhengdan958 in 2009 and Xianyu335 in 2010) close plant was carried out in 2009-2010. The main root morphological index and root dry matter accumulation in 0-60 cm depth soil profile in the key growth period were measured under the densities of 45 000, 67 500, 90 000 plant/ha. The results showed that the root biomass on the basis of individual plant in 0-60 cm depth soil decreased with the increasing density, but the community root dry weight kept an increasing trend. Under all three densities, root morphology index of Zhengdan958, including root length, root surface area, root volume and root length density, showed a change of single-peak curve from jointing stage to milk stage with growth development and reached the maximum at tasseling-silking stage. However, all root morphology index of Xianyu335 showed a declined trend from jointing stage to milk stage, and reached the maximum at jointing stage. Root length, root surface area and root volume index of individual plant of two maize varieties substantially decreased with increasing density at tasseling-silking stage and milk stage; on the contrary, root length, root surface area, root volume and root length per volume of maize population increased with the increasing density.