拔节期水氮运筹对冬小麦籽粒灌浆期叶片光合特性及水分利用效率的影响

Effect of Irrigation and Fertilizer Application at Jointing Stage on Photosynthetic Characteristics and Leaf Water Use Efficiency of Winter Wheat at Grain Filling Stage

为给冬小麦节水高效栽培提供理论依据,在防雨、基施氮量和开花期灌水量相同的条件下,通过拔节期不同追氮和灌水处理,研究了水氮运筹对冬小麦籽粒灌浆期叶片光合特性及水分利用效率(WUE)的影响。结果表明,冬小麦旗叶净光合速率、蒸腾速率、叶绿素a、叶绿素b均随拔节期灌水量的增加而升高。在相同灌水量下,增加追氮量能显著提高叶片净光合速率、蒸腾速率、叶绿素a和b含量。追氮能显著提高叶片WUE,增加拔节期灌水量达W2(750 m3/ha)水平以上能显著提高叶片WUE。在N1(0 kg/ha)和N2(90 kg/ha)追氮量下,增加拔节期灌水量有利于提高叶片WUE,但在N3(180 kg/ha)水平下,增加拔节期灌水量不利于叶片WUE的提高。水、氮之间存在显著的互作效应,光合效率以N3W3处理(追氮量为180 kg/ha,拔节期灌水量为1 050 m3/ha)最高,而叶片WUE以N2W3处理(追氮量为90 kg/ha,拔节期灌水量为1 050 m3/ha)最高。通径分析表明,光合性状对叶片WUE的直接贡献大小依次为:净光合速率>气孔导度>叶绿素a>胞间CO2浓度>叶绿素b>蒸腾速率。

In order to provide a theoretical basis for efficient water-saving cultivation of winter wheat, the effects of irrigation and nitrogen regimes on photosynthetic characteristics and leaf water use efficiency （WUE） were studied under rainout shelter. During grain filling stage of winter wheat, nitrogen application rate in the baseline and irrigation at flowering stage were under the same conditions, while in the stage of Jointing nitrogen and irrigation treatments were different. The results showed that flag leaf net photosynthetic rate, transpiration rate, chlorophyll a and b showed obvious increase with the increase of water volume at jointing stage. Under the same volume of irrigation, increasing nitrogen fertilizer could significantly increase leaf net photosynthetic rate, transpiration rate, chlorophyll a and chlorophyll h contents. Nitrogen application could obviously improve the leaf WUE, and when water level reached more than W2 （750 m^3/ha）,irrigation could significantly enhance the leaf WUE at jointing stage. Under N1 （0 kg/ha） and N2 （90 kg/ha） application, increasing irrigation volume is conducive to leaf WUE. At N3 （180 kg/ha） level, however, increasing irrigation volume was not conducive to leaf WUE at jointing stage. A significant interaction effect was observed between irrigation and nitrogen fertilizer, photosynthetic efficiency was the highest at N3W3 （nitrogen application of 180 kg/ha, irrigation at jointing stage of 1 050 m^3/ha） combina tion, whereas leaf WUE was the most reasonable at N2W3（nitrogen application of 90 kg/ha, irrigation at characters to leaf WUE was as follows： net photosynthetic rate, stomatal conductance, chlorophyll a, in tracellular concentrations of carbon dioxide, chlorophyll b, transpiration rate.