Here, the nitrogen source of NO3(superscript -)/NH4(superscript +) 50/50 and the nitrate content in leaves can be considered as the best nutrient solution and index for nitrate accumulation screening.

• 硝铵比50/50是最适宜筛选的氮素形态比例，而叶片中的硝酸盐含量也是最适宜的筛选指标。