细胞质雄性不育玉米的根系特性和氮效率研究

Root Traits and Nitrogen Efficiency of Cytoplasmic Male Sterility Maize

【目的】探讨细胞质雄性不育玉米的根系特性和氮素吸收利用规律。【方法】在土柱栽培条件下,选择目前生产中广泛应用的骨干自交系478和齐319的细胞质雄性不育系(CMS)和其同型保持系(可育系)为试验材料,比较分析雄性不育系及其可育系灌浆期根系特性的差异及对缺氮的响应。【结果】CMS玉米的籽粒产量和千粒重均高于其同型可育植株(P<0.05),生物产量差异不显著(P>0.05),收获指数明显较高(P<0.05),且缺氮条件下优势更为明显。CMS玉米灌浆期具有较高的根系干重、根系体积和根系总活力,且深层根系分布相对较多,根系活力较强,有效延长了根系的功能期,促进了植株对养分和水分的吸收。CMS玉米氮素积累总量高于其同型可育系(P<0.05),成熟期氮素在茎秆和籽粒中分配较多;低氮水平下,CMS玉米的氮素转移率、贡献率和氮素利用率均显著高于其同型可育系(P<0.05);CMS玉米单株氮效率较高,氮响应度相对较低。【结论】细胞质雄性不育玉米籽粒产量高、氮效率高与其深层根量多、根系活力强密切相关。

[Objective] Male sterile characteristic plays an important role in the utilization of heterosis. The purpose of this study was to investigate the root traits and nitrogen uptake and utilization rule of cytoplasmic male sterile （CMS） lines. [ Method] In soil column experiment, two inbred lines, cytoplasmic male sterility （478CMS and Q319CMS） and homotypic fertile lines（478 and Q319） were used to analyze the difference among root traits, nitrogen uptake and utilization efficiency between two inbred lines. [Result] Grain yield and 1000-kernel weight of CMS lines were higher than those of homotypic lines （P〈0.05）, no difference in biomass （/＇〉0.05） was found, whereas harvest index was significantly higher in CMS lines under nitrogen deficiency （P〈0.05）. The root weight, root volume and total root activity of CMS lines overweighed those ofhomotypic lines during grain filling period （P 〈0.05）, furthermore advantages in depth soil layer was obvious, which could prolong root functional period effectively and promote root absorption in water and nutrient. Total nitrogen accumulation amount of CMS lines was distinctly higher than their homotypic lines （P〈0.05）, with more nitrogen distributed to stalk and grain in CMS lines. Both N transportation efficiency and N contribution rate of CMS lines were higher in contrast to the homotypic lines under nitrogen deficiency （P〈0.05）. Compared with homotypic lines, CMS lines maintained higher individual nitrogen utilization efficiency than their homotypic lines, but the response to N fertilizer was relatively lower. [Conclusion] The higher grain yield and higher nitrogen efficiency of CMS lines were closely correlated with more root weight distributed in deeper layer and stronger root physiological activity.