RELATIONSHIPS BETWEEN NITRATE CONTENTS AND WATER, TOTAL N AS WELL AS TOTAL P IN DIFFERENT ORGANS OF VEGETABLE PLANTS

Spinach, Chinese cabbage and lettuce were planted in a Hongyou soil located in the vegetable garden of the university, and the plants were sampled 3 times after 10 days of N fertilization for determination of nitrate, water, total N and total P to study the nitrate distribution relationships to the later three components. The results showed that the nitrate contents were different with different organs, the roots, stems and Petioles being the highest in nitrate contents (557. 9~ 1196.7ug per gram fresh weight) followed by outside blades (213. 5~551. 8ug per gram fresh weight) and central blades being the lowest (120. 6-198. 3ug per gram fresh weight). Also, water, total N and total P contents in different organs were obviously different. The nitrate contents were positively correlated with water contents in stems, petioles, outside and central blades, the correlation coefficients ranging from 0.910 to 0.956, but negatively correlated with the amounts of total N and total P, the correlation coefficients ranging from - 0.733 to -0.951. In contrast, the nitrate contents in roots were not in accordance with these patterns.