不同耐密性玉米品种对根系生长空间的响应

选用DY405与ZD958,通过PVC土柱栽培法,设1株/柱(D1)与2株/柱(D2)两个处理,研究不同根系生长空间条件下玉米品种根系生长与氮素积累特征。结果表明,根系生长空间由1株/柱(D1)降低至2株/柱(D2),DY405与ZD958根系干重均降低,吐丝期及成熟期1株/柱条件下DY405根系干重较大,2株/柱下品种差异不显著。不同土层根系干重分布,0~20 cm土层DY405分布比例高于ZD958,21~40 cm、41~60 cm土层DY405分布比例低于ZD958;DY405与ZD958单株子粒产量均降低,穗粒数分别下降36.1%、17.5%。DY405与ZD958成熟期干物质积累差异不显著,ZD958花后干物质积累量及比例显著高于DY405;全株氮素积累量差异与干物质积累表现趋势相同,DY405氮素积累量及花后氮素吸收量显著低于ZD958。减小根系生长空间条件下,ZD958产量与氮素积累量高于DY405,主要由于吐丝至成熟期根系干重下降缓慢且下层根系分布比例较大,促进植株对水分及氮素的吸收,从而使产量与氮素利用效率提高。

Response to Root Growth Space of Contrasting Planting Density Tolerant Maize Varieties

Using PVC-tube soil-column cultivation method, experiment was carried out to study the root growth and nitrogen uptake of two maize hybrids, Danyu 405 (DY405, low-density suitable) and Zhengdan 958 (ZD958, high-density tolerance) in two root growth spaces, D1 (1 plant/pot) and D2 (2 plants/pot). The results showed that, with the decreasing of root growth space from D1 to D2, grain yield per plant of DY405 and ZD958 declined, kernel number per ear decreased by 36.0, and 17.1%, respectively. DY405 and ZD958 were similar with total dry matter (Total DM) at physiological maturity stage, while ZD958 was higher in post silking dry matter accumulation (Post DM); no difference was found between two hybrids in maturity stage total N accumulation (Total N), higher post silking nitrogen uptake (Post N) was in ZD958 compared with DY405, resulting from the accumulation N in shoot (Shoot N) in ZD958 at maturity stage; DY405 gained higher root DM percentage at 0-20 cm soil depth than ZD958, conversely in the 20-40 cm, 40-60 cm depth. It induced that, to achieve maize high tolerance to density and nitrogen use efficiency improved simultaneously, not only root morphological traits such as root DM but also root physiological capability should be focused on in the future research.