Effects of n and water supply on dry matter and n accumulation and distribution in maize (zea mays l.) leaf and straw-sheath | 水、氮供应对玉米冠层营养器官干物质和氮素累积、分配的影响

Chinese. 【目的】阐明水、氮供应对玉米冠层营养器官干物质和氮素累积、分配及随生育时期变化的影响,对关键生育时期采取有效水肥措施以提高产量。【方法】以土垫旱耕人为土为供试土壤,玉米为研究材料,采用盆栽试验研究不同氮素和水分供应对玉米冠层营养器官干物质及氮素累积、分配及随生育时期变化的影响。【结果】除11叶期外,施氮可显著提高叶片和茎鞘单位干重氮素含量;施氮条件下,充分供水有利于叶片和茎鞘单位干重氮素累积;而氮素胁迫时,充分供水反而不利于单位干重氮素累积。无论施氮与否,充分供水处理叶片＋茎鞘干物质累积随生育时期呈单峰曲线变化,而干旱胁迫处理呈线性增长趋势;除水、氮皆胁迫处理叶片＋茎鞘氮素累积从11叶期到灌浆期变化不明显外,其余处理均呈单峰曲线变化。无论水、氮供应情况如何,各生育时期氮素累积主要部位均为叶片;不施氮时,生育前期干物质累积主要部位是叶片,生育后期为茎鞘;施氮后,各生育时期干物质累积主要部位均为茎鞘,施氮对茎鞘干物质累积的影响比对叶片更为显著。【结论】叶片和茎鞘干物质与氮素累积具有不同步性,且随生育时期累积趋势因水、氮供应不同而异。各处理氮素累积主要部位均为叶片,而干物质在叶片和茎鞘中的分配因氮素供应不同存在显著差异。施氮和充分供水均可显著提高冠层营养器官干物质及氮素累积,二者存在显著正交互效应,本试验条件下氮肥比水分效应更为突出。

English. 【Objective】 The objective of this paper was to study the effects of different levels of N and water supply on the accumulation and distribution of dry matter and N in maize leaf and straw-sheath. 【Method】 A pot experiment was therefore conducted during 2008-2009 to study the dry matter and N accumulation and distribution dynamics as affected by different levels of N supply and soil water availability. 【Result】 The results showed that N concentration of leaf and straw-sheath was significantly increased with application of N fertilizer except 11-leaf stage. Adequate water supply significantly enhanced the N concentration of leaf and straw-sheath in N application treatments, however, adequate water supply did not enhance but decreased the N concentration of leaf and straw-sheath in no N application treatments. Whether N were applied or not, the dry matter accumulation of leaf and straw -sheath showed a single-peak curve with maize growing under the condition of adequate water supply, but it showed a continuous increasing trend with growing under the condition of drought stress. The N accumulation of leaf and straw-sheath showed a single-peak curve with growing in all treatments except the one which were treated with not only drought stress but also no N application (in this treatment, no significant differences were observed in N content of leaf and straw -sheath among 3 stages). Whether N and water were supplied sufficiently or not, leaf was the main part of N distribution, but the distribution of dry matter varied with N application and growing stage. When no N fertilizer was applied, the cumulative amount of dry matter in straw-sheath was higher than in leaf from spinning to grain filling stage, however, it was lower than leaf at 11-leaf stage. When N fertilizer was sufficiently supplied, the cumulative amount of dry matter in straw-sheath was always higher than in leaf during the whole growing season.【Conclusion】 The accumulation of dry matter and N in leaf and straw-sheath were asynchronous, and the accumulation curves varied with different levels of water and N supply. Leaf was the main part of N accumulation, but the main part of dry matter accumulation varied with N application and growing stage. N application and irrigation both could significantly increase the dry matter and N content in maize canopy, and the interactive effects between irrigation and N application were significant, in addition, the effect of N application was higher than irrigation in present experiment.