硝态氮处理对雪菊幼苗生长及代谢的影响

【目的】筛选出适宜雪菊幼苗生长的硝态氮肥施用量。【方法】以雪菊为试验材料,选用硝态氮(Ca(NO₃)₂·4H₂O)为供试肥料,采用盆栽试验,按照完全随机区组设计,设置6个硝态氮处理水平,每盆硝态氮的施用量分别为0 (CK),0.10、0.15、0.20、0.25、0.30 g/kg营养土,研究不同硝态氮处理对雪菊幼苗生长及代谢产物的影响。【结果】不同硝态氮处理对雪菊幼苗生长及代谢产物均有一定的影响。硝态氮施用量为0.25 g/kg时,雪菊幼苗的株高表现最佳,为7.26 cm;硝态氮施用量为0.3 g/kg时,雪菊幼苗的鲜重、茎粗、幼苗分枝数、SPAD值、可溶性蛋白质含量表现最佳,SPAD值和可溶性蛋白质含量分别为48.92和8.86 mg/g。硝态氮对雪菊幼苗可溶性糖有一定促进作用,在硝态氮施用量为0.25 g/kg时,可溶性糖含量最高,为32.63％。对照的雪菊幼苗根冠比、根长、叶片中绿原酸、总黄酮以及根中总黄酮含量最高,叶和根中总黄酮分别为90.70和34.77 mg/g,叶片中绿原酸含量为10.85 mg/g。硝态氮施用量为0.3 g/kg时,雪菊幼苗中PAL活性最低,与对照相比降低10.76％。【结论】少施或不施硝态氮有利于提高雪菊幼苗叶片PAL活性,增加幼苗根和叶的总黄酮和绿原酸含量,但少施或不施硝态氮对雪菊幼苗的生长以及干物质积累有明显的抑制作用。硝态氮施用量以0.25～0.3 g/kg营养土为宜。

Effects of Nitrate Nitrogen Treatment on Growth and Metabolism of Coreopsis tinctoria Nutt. Seedlings

【Objective】 To screen out the amount of nitrate nitrogen fertilizer suitable for the growth of the Coreopsis tinctoria seedlings. 【Method】 Coreopsis tinctoria was taken as the test material, nitrate nitrogen (Ca(NO₃)₂·4H₂O) as test fertilizer to carry out pot experiments. According to the completely random block design, six levels of nitrate nitrogen treatment were set up. The application rate of nitrate nitrogen per pot was 0.10g, 0.15, 0.20, 0.25, 0.30 g/kg. The effects of different nitrate nitrogen treatments on the growth and metabolites of Coreopsis tinctoria seedlings were studied. 【Results】Different nitrate treatments had certain effects on Coreopsis tinctoria seedling growth and metabolites. When the nitrate nitrogen application rate was 0.25 g/kg, the plant height of the Coreopsis tinctoria seedlings was the best, which was 7.26 cm; When the application rate of nitrate nitrogen was 0.3 g/kg, the fresh weight, stem diameter, number of branches, SPAD value and soluble protein content of Coreopsis tinctoria seedlings were the best. The SPAD value and soluble protein content were 48.92 and 8.86 mg/g. Nitrate nitrogen could promote the soluble sugar of Coreopsis tinctoria seedlings. When the nitrate nitrogen application rate was 0.25 g/kg, the soluble sugar content was the highest, which was 32.63%. Root-shoot ratio, root length, chlorogenic acid, total flavonoids in leaves and total flavonoids in roots were highest in control Coreopsis tinctoria seedlings. The total flavornoids in leaves and roots were 90.70 and 34.77 mg/g. The chlorogenic acid content in the leaves was 10.85 mg/g. When the nitrate nitrogen application rate was 0.3 g/kg, the PAL activity in the Coreopsis tinctoria seedlings was the lowest, which was 10.76% lower than that of the control. 【Conclusion】 The results of this test showed that little or no application of nitrate nitrogen was beneficial to improve the PAL activity of leaves of the Coreopsis tinctoria seedlings and increased total flavonoids and chlorogenic acid content in roots and leaves of seedlings, however, the application of less or no nitrate nitrogen significantly inhibited the growth and dry matter accumulation of the Coreopsis tinctoria seedlings. Therefore, considering the growth status of the Coreopsis tinctoria seedlings, the nitrate nitrogen application rate is preferably 0.25 to 0.3 g/kg of nutrient soil.