20 kinds of vegetable crops were tested for nitrate content(NC) at Nanjing non-pollution vegetable production base and DFT of Hoagland I respectively from 1995 to 1996. NC was determined by NO3- electrode. It was established there exists wide genetic variation between different vegetable varieties and cultivars of the same vegetable. The results indicated that some vegetables, such as asparagus lettuce, radish, celery and pak-choi accumulated a relatively high nitrate content, while leguminous vegetables an...