氮、钾、甜菜碱对减缓夏玉米水分胁迫的效果

 采用盆栽试验研究了水分胁迫和正常供水条件下，氮、钾和甜菜碱对2种不同基因型夏玉米（陕单9号和陕单911）各生育期干物质、籽粒产量及水分利用效率的影响，确定这些因子在增强作物抗旱性方面的功能。结果表明，水分胁迫条件下玉米干物质和籽粒产量明显降低，但各品种反应不同：陕单9号干物质和籽粒产量高，抗旱性强；陕单911相反。施用氮、钾和甜菜碱能不同程度提高玉米干物质和籽粒产量以及水分利用效率，减缓水分胁迫，提高程度与品种关系密切。施用氮肥后，在水分胁迫条件下陕单911干物质和籽粒产量显著增加，水分利用效率明显提高，2种氮肥用量有显著差异；陕单9号在低氮用量时增产，增加氮量并未进一步提高产量，低、高氮肥用量间无显著差异。正常供水时，氮肥作用明显下降，表明氮肥不仅能供应养分，还有增强抗旱的功能。施用钾肥和喷施甜菜碱对受水分胁迫的玉米有同样功能，且效果更突出。在供水条件下这些效果下降更明显，甚至消失，表明它们对增强作物抗旱性的贡献更大。

Effects of Application of Nitrogen, Potassium and Glycinebetaine on Alleviation of Water Stress in Summer Maize

A pot experiment was conducted under water stressed and adequate water-supplied conditions with two genetype varieties (Shandan9 and Shandan911) to study the effects of nitrogen, potassium and glycinebetaine on their dry matter and grain yields as well as water use efficiency at different stages for revealing the function of these factors in increase of plant resistance to drought or dryness. Results showed that with water stress, dry matter and grain yields were significantly reduced. However, the response of the two varieties to the stress was different: Shandan9 was higher in dry matter and grain yields, and therefore could be regarded as a drought-resistant variety while Shandan911 was not so. Application of nitrogen, potassium and glycinebetaine raised dry matter and grain yields to different levels, and thus alleviated the water stress and increased water use efficiency. The effects were higher on Shandan911 than on Shandan9. Under water-stressed conditions, application of N fertilizer, either at low rate or at high rate, significantly increased dry matter, grain yields and water use efficiency, and significant difference between N rates was found for Shandan911, but no such effect for Shandan9. However, with adequate water supply, the effects of N fertilization were obviously decreased, showing that in addition to supplying nutrient, it has functions in increasing drought-resistance of a crop. Potassium and glycinebetaine exhibited more obvious function in increase of dry matter and grain yields as well as water use efficiency under water stressed conditions while such effects were obviously declined, and even vanished, with adequate water supply, indicating the important contribution of these factors in increase of drought-resistance ability of a crop.