不同生长发育阶段几种野菜中硝酸盐、亚硝酸盐及维生素C的含量

测定了荠菜、泥胡菜和多头苦荬菜等3种野菜不同发育阶段叶中的硝酸盐、亚硝酸盐和维生素C的含量。参考蔬菜中硝酸盐含量分级评价标准，参考我国制定的无公害蔬菜亚硝酸盐含量限量标准（以NaNO2计≤4．0mg／kg），考虑到各种野菜的维生素C的含量，对这3种野菜评价如下：泥胡菜和多头苦荬菜的各个时期的叶，硝酸盐含量低于轻度污染水平444mg／kg，亚硝酸盐含量低于我国制定的无公害蔬菜亚硝酸盐含量的限量标准，所以，它们属于一级野菜，可以安全食用；果期荠菜的叶，硝酸盐含量低于807mg／kg，属于中度污染水平，亚硝酸盐含量低于我国制定的无公害蔬菜亚硝酸盐含量的限量标准，属二级蔬菜范围，不宜生食，煮熟或盐渍可安全食用：荠菜的期于各期叶的硝酸盐含量高于807mg／kg而低于1268mg／kg，亚硝酸盐含量低于我国制定的无公害蔬菜亚硝酸盐含量的限量标准，属于三级蔬菜，不可生食和盐渍，可熟食。

The Contents of Nitrate, Nitrite and Vitamin C at Different Growth Stages in Leaves of 3 Wild Vegetables

In order to research the scientific data of wild vegetables in guangdong , the contents of nitrate, nitrite and vitamin C in leaves of 3 wild plants were determined. The results and conclusions were as follows : Hemisteptalyrata (Bung.) Bung.. and Ixeris polycephala Cass; at every stage ,belong to the first class edible wild vegetables and they can beeaten anyway(in fresh, after salted or cooked ); at fruit stage , Capsella bursa-pastoris (L.) Medic. belongs to the second classand it can be eaten by cooked or salted.; at other stages , Capsella bursa-pastoris (L.)Medic. belongs to the third class edible wildvegetables and must be eaten after cooked.