National Research Institute on Food and Nutrition, Rome, Italy.
J Sci Food Agric. 2012 Nov;92(14):2796-9. doi: 10.1002/jsfa.5526. Epub 2011 Dec 22.
Green leafy vegetables contribute greatly to the total intake of nitrates from the daily diet. This study evaluates the influence of different cultivation systems on nitrate accumulation in leafy vegetables. Two varieties of lettuce (Lactuca sativa L.) (Lattuga Romana, Foglia di Quercia) and two varieties of red radicchio of Treviso (Cychorium intibus L.) (Early, Late) were selected. Lettuce varieties were both organically and biodynamically grown; red radicchio varieties were conventionally grown both in the field and in spring water.
Both lettuce varieties biodynamically grown accumulated 1.3-2 times less nitrate than the respective organically grown plants. The two lettuce varieties showed differences in nitrate accumulating capacity: Foglia di Quercia was almost three times richer in nitrate than Lattuga Romana. The traditional growing systems applied to the red radicchio of Treviso varieties strongly influenced nitrate accumulation in leaves, the Early variety having up to 15 times higher nitrate than the Late variety.
Our findings on nitrate levels in both lettuce and red radicchio of Treviso varieties suggest that both genetic factors and cultivation systems strongly affect the nitrate accumulation capacity. This study also highlights how the cultivation strategy can reduce nitrate levels in leafy vegetables, suggesting the possibility of modulating the N supply along the harvesting time.
绿叶蔬菜对从日常饮食中摄入的硝酸盐总量贡献很大。本研究评估了不同栽培系统对绿叶蔬菜硝酸盐积累的影响。选择了两种生菜（生菜）（罗马生菜，橡树叶生菜）和两种特雷维索红菊苣（菊苣）（早生，晚生）。生菜品种均采用有机和生物动力学方法种植；红菊苣品种在田间和泉水均采用常规方法种植。
两种生物动力学种植的生菜品种积累的硝酸盐比各自的有机种植品种少 1.3-2 倍。两种生菜品种在硝酸盐积累能力上存在差异：橡树叶生菜的硝酸盐含量几乎是罗马生菜的三倍。传统的栽培系统对特雷维索红菊苣品种的叶片硝酸盐积累有很大影响，早生品种的硝酸盐含量比晚生品种高 15 倍以上。
本研究对生菜和特雷维索红菊苣硝酸盐含量的研究结果表明，遗传因素和栽培系统都强烈影响硝酸盐的积累能力。本研究还强调了栽培策略如何降低绿叶蔬菜中的硝酸盐水平，提示了沿收获时间调节氮素供应的可能性。
