氮对亚适宜温光下黄瓜生理特性和产量的影响

Effects of Nitrogen Level on Physiological Characters and Yield of Cucumber under Suboptimal Temperature and Light Intensity

以中农26为试材,以正常施氮（2.392 g N·株^-1）处理为对照,研究了亚适宜温光环境下浇灌1倍（增施16%氮肥）和2倍（增施32%氮肥）含氮量营养液对结果期黄瓜生长、产量和品质的影响。结果表明：亚适宜温光环境下,与对照相比,浇灌1倍氮营养液处理的黄瓜株高、茎粗、产量和品质均明显升高;根系活力、叶绿素含量与氮代谢相关酶活性及含氮量均显著高于对照;与氮代谢相关的N转运蛋白基因的表达均明显上调。而浇灌2倍氮营养液处理下,黄瓜生长受抑,产量和品质降低。说明在亚适宜温光环境下,0-16%的范围内合理增施氮肥能使黄瓜N转运蛋白基因表达上调,促进黄瓜对氮的吸收与代谢,最终促进植株生长和产量的提高,但过量（〉16%）增施氮肥会抑制黄瓜生长,降低产量和品质。

In order to identify a suitable nitrogen level for cucumber cultured under suboptimal temperature （18/12 ℃ ） and suboptimal light intensity （ 180 ± 20 μmol· m^ -2· s ^-1 ）, ＇ Zhong Nong No. 26＇ in fruiting period cultured with 2. 392 g nitrogen per plant were used as control, the effects of nitrogen level on the growth, physiological characteristics, yield and nitrogen metablism of the cucumber were studied. The results showed that the plant height, stem diameter, yield and quality of the cucumber under the treatment of T1 （16% nitrogen increased compared with the control） were increased significantly compared with those of the control. Furthermore, the root activities, chlorophyll content, activities of glutamine synthetase （GS）, glutamate synthase （GOGAT） and glutamate dehydrogenase （GDH） were increased under the treatment of adding 1 times nitrogen level solution, and the same situation happened to the content of nitrogen. In addition, the expression of nitrogen transporter genes in the cucumber roots, leaves and fruits were upregulated under the same treatment. However, the growth, yield and quality of cucumber under the treatment of adding 2 times nitrogen nutrient slolution （32% nitrogen increased compared with the control）were decreased compared with those of the control. The results indicated that under the suboptimal temperature and suboptimal light intensity environment, proper increasing nitrogen application （0 - 16% ） may induce the upregulation of nitrate transporter genes, and then increase the absorption and metabolism of nitrogen, promote the growth, yield and quality of cucumber finally. However, increasing nitrogen application excessively （ 〉 16% ） may inhibit the growth and yield, and decrease the quality of cucumber.