硅、磷配施对玉米苗期生长及氮磷钾积累的影响

以‘正红2号’和‘正红115’玉米为材料,采用砂培方式,设置3个纯磷水平1.0 mmol·L~(-1)(正常磷水平,P_(1.0))、0.1 mmol·L~(-1)(中度缺磷,P_(0.1))和0.01 mmol·L~(-1)(重度缺磷,P_(0.01))]和3个纯硅水平1.5 mmol·L~(-1)(Si_(1.5))、0.75mmol·L~(-1)(Si_(0.75))和0 mmol·L~(-1)(Si_0)],通过对玉米苗期干物质、叶面积、根系形态和氮磷钾含量的测定分析,研究硅、磷配施对玉米苗期根系生长、各器官干物质及氮、磷和钾养分积累与利用的影响,为磷、硅肥合理配施提供理论依据。结果表明:缺磷抑制玉米苗期生长,降低根长、根体积、根表面积和叶面积,减少磷和氮、钾的吸收以及干物质积累量,这种效应随磷浓度的降低而增强;玉米通过提高根冠比,增加磷、氮在根系中的分配率,提高氮、磷、钾的干物质生产效率来适应低磷环境;低磷胁迫对‘正红115’根系生长和磷吸收积累量的影响大于‘正红2号’,但‘正红115’在低磷条件下大幅度提高磷在根系中的分配率。在正常磷(P_(1.0))条件下加硅可促进玉米根系生长,增加磷和氮、钾积累量,提高其在地上部分配率,增加叶面积和干物质积累量;在中度缺磷(P_(0.1))条件下加硅也可增加玉米的磷和氮、钾积累量,促进根系和地上部生长,缓解低磷胁迫;在重度缺磷(P_(0.01))条件下,增施硅对玉米根系生长和干物质积累无显著的改善作用,但会增加根系中磷、钾素积累量。由此表明,硅和磷存在显著的协同作用和配合效应,生产上硅和磷应配施。

Effect of phosphorus and silicon application on the uptake and utilization of nitrogen, phosphorus and potassium by maize seedlings

This study tested the effect of three levels of phosphorus (P) 1.0 mmol(P)·L-1(P1.0), 0.1 mmol(P)·L-1(P0.1) and 0.01 mmol(P)·L-1(P0.01)] and three levels of silicon (Si) 1.5 mmol(Si)·L-1(Si1.5), 0.75 mmol(Si)·L-1(Si0.75) and 0 mmol(Si)·L-1(Si0)] on a range of characteristics of 'Zhenghong 2' and 'Zhenghong 115' maize cultivars. The study analyzed dry matter, leaf area, root mor-phology and NPK contents of maize to determine the effects of the combined application of Si and P on maize root growth, dry mat-ter accumulation and NPK accumulation and utilization at seedling stage. The results indicated that P deficiency not only suppressed maize seedling growth, but also decreased root length, root volume, root surface area, leaf area, NPK assimilation and dry matter accumulation, and the effects were strengthened with decreasing P concentration. The enhanced maize root-to-shoot ratio at seedling stage increased the distribution rates of P and N in root system and the accumulation efficiency of NPK in dry matter, which im-proved the adaptation of rice to P-deficient environments. P deficiency stress enhanced root growth and P absorption and accumula-tion more in 'Zhenghong 115' than in 'Zhenghong 2' maize cultivar. However, the distribution rate in the root system of 'Zhenghong 115' maize cultivar increased substantially under P deficiency. Si accelerated maize root growth, increased NPK accumulation, im-proved the distribution rate of NPK in aboveground system, increased leaf area and dry matter accumulation under normal P condi-tion (P1.0). Under medium P deficiency (P0.1), the application of Si alleviated P deficiency stress through increasing NPK accumula-tion in maize seedlings, furthermore, it also accelerated growth of both root and shoot system. Under severe P deficiency (P0.01), the application of Si had no significant effect on root growth and dry matter accumulation, but it increased the PK accumulation in root system. It was therefore concluded that there existed significant synergetic and coordination effects of P and Si on beneficial traits of maize at seedling stage.