研究了施氮对现蕾期和开花期甜菊（Stevia rebaudiana Bertoni）品种‘中山8号’（‘Zhongshan No. 8’）不同器官干质量、全氮含量、氮素累积量和分配比例、全碳含量、碳氮比和可溶性糖含量以及叶片中甜菊糖苷含量和累积量的影响，并对叶片中部分指标进行Pearson相关性分析。结果表明：总体上看，与不施氮处理相比，施氮处理显著增加了现蕾期和开花期甜菊茎和叶片的干质量、全氮含量和氮素累积量，但是显著降低了茎和叶片中碳氮比以及叶片中可溶性糖和3种甜菊糖苷组分含量。同一施氮水平下，与现蕾期相比，开花期甜菊茎中全氮含量有所提高，但是叶片中全氮含量无显著变化；叶片中氮素分配比例显著降低；茎和叶片中全碳含量以及碳氮比无显著变化；茎中可溶性糖含量有所提高，但叶片中可溶性糖含量以及3种甜菊糖苷组分含量总体上显著降低。施氮水平和生育期对甜菊单株总甜菊糖苷累积量均无显著影响。甜菊叶片中部分指标的Pearson相关性分析结果显示：甜菊叶片中总甜菊糖苷含量与全氮含量和干质量分别呈显著和极显著负相关关系，但与可溶性糖含量呈极显著正相关关系。综上所述，开花或施氮均会降低甜菊叶片中甜菊糖苷含量，建议在甜菊现蕾期及时采收叶片，并降低甜菊促花肥的投入量。

Effects of nitrogen application on dry mass, total nitrogen content, accumulation and allocation ratio of nitrogen,  total carbon content, carbon/nitrogen ratio and soluble sugar content in different organs and content and accumulation of steviol glycoside in leaf of cultivar ‘Zhongshan No. 8’ of Stevia rebaudiana Bertoni at flowering bud stage and flowering stage were studied, and Pearson correlation analysis was conducted for some indexes of leaf. The results show that compared with no nitrogen application treatment, nitrogen application treatment significantly increases dry mass, total nitrogen content, and nitrogen accumulation of stem and leaf of S. rebaudiana at flowering bud stage and flowering stage, but significantly decreases carbon/nitrogen ratio in stem and leaf and contents of soluble sugar and three steviol glycoside components in leaf in general. Under the same nitrogen application level, total nitrogen content in stem  of S. rebaudiana at flowering stage increases compared with that at flowering bud stage, but there is no significant variation in total nitrogen content in  leaf; allocation ratio of nitrogen in leaf significantly decreases; there are no significant variations in total carbon content and carbon/nitrogen ratio in stem and leaf; soluble sugar content in stem increases, but contents of soluble sugar and three steviol glycoside components in leaf significantly decrease in general. The nitrogen application level and growth stage both have no significant effects on total steviol glycoside accumulation per plant of S. rebaudiana. The Pearson correlation analysis result of some indexes of leaf of S. rebaudiana shows that total steviol glycoside content shows significant and extremely significant negative correlations with total nitrogen content and dry mass of leaf of S. rebaudiana respectively, but shows extremely significant positive correlation with soluble sugar content. Taken together, flowering or nitrogen application both will decrease steviol glycoside content in leaf of S. rebaudiana, and timely harvesting  leaf at flowering bud stage of S. rebaudiana and reduction of flowerpromoting fertilization of S. rebaudiana are recommended.