供氮量及化学调控对玉米苗期生长及氮素吸收分配特征的影响

以郑单958为材料,设置不同氮素梯度于苗期利用完全营养液培养,3叶期叶面喷施聚糠萘合剂,研究供氮量对苗期玉米氮素吸收分配特征的影响以及聚糠萘合剂化学调控的效果。结果表明,与去离子水处理相比,增加氮素供应可使株高增加,根系增长,根冠比值显著降低,叶片与根中硝酸还原酶活性(NRA)增大,鞘中NRA减小。随氮素浓度的增加,株高、最大根长和叶片数逐渐增加,各器官干物质积累量依次增加,叶片中NRA依次增强,氮素吸收和向地上部分配的比例显著增加。聚糠萘合剂处理与相应清水对照相比,提高了植株干物质积累,缩短了最大根长,增加了侧根条数,提高了玉米植株中总吸氮量及氮素利用率。对于不同浓度梯度的氮素处理,低浓度(2.5mmol/L)和中浓度(5.0 mmol/L)培养液中调节剂处理氮素利用率分别比对照增加52.75%和54.91%,表明中、低氮条件下聚糠萘合剂提高了氮素利用率。

Effect of Nitrogen Rate and Chemical Regulation on Seedling Maize Growth and Characters of Nitrogen Absorption

A new plant growth regulator PKN(PASP-KT-NAA)was applied on Zhengdan958 with different nitrogensupply in nutrient solution. And its influence on maize growth and nitrogen absorption was studied. The results indicatedthat compare with deionizer water, nitrogen supply could increase plant height, root length and nitrate reductiveactivity(NRA) in leaf and culm, and decrease root/shoot rate significantly. As the nitrogen supply increasing, drymatter weight and nitrogen absorption increase and nitrogen recovery efficiency reduce. PKN treatment can significantlyincrease plant dry matter weight and total nitrogen content by grown more lateral roots. The nitrogen absorptionrate raised 52.75 percent with low nitrogen supply(1.25 mmol/L) and 54.91 percent with mid nitrogen supply(2.5mmol/L) compared to controlled treatments. It is concluded that the nitrogen absorption efficiency can be improved byPASP-KT-NAA in nitrogen deficiency condition.