蔬菜与小麦硝态氮累积的差异

Differences between Vegetable and Wheat in Nitrate Accumulation

在菜园土壤上进行的大田试验，研究了小白菜、菠菜和小麦硝态氮累积的差异。结果表明，苗期小麦的硝态氮含量小于小白菜、大于菠菜。但就整个生长期来看，小白菜的硝态氮含量大于菠菜，两种蔬菜的含量明显大于小麦。随生长期延长，菠菜和小白菜的硝态氮含量呈波动型升高，而小麦则呈波动型下降。从不同器官部位来看，根系的硝态氮含量在生长前期大于、后期小于茎；地上部分茎的含量又大于叶，叶部的叶柄（小麦叶鞘）大于叶片。在生殖器官部分，两种蔬菜的花和幼嫩的果实及小麦的幼穗硝态氮含量极低或不含，但在成熟的果实中，两种蔬菜的果壳硝态氮累积较多，而小麦的颖和芒及三种作物的种子却不含硝态氮。

Field experiments were carried out on a vegetable garden soil with Chinese cabbage, spinach and wheat as indicating crops, to study the differences between vegetable and wheat in nitrate accumulation. The results obtained show that during seedling stage the nitrate contents in wheat were higher than in spinach, and lower than in Chinese cabbage. However, as the average values of the whole growing stage were concerned, the nitrate contents in two vegetables were significantly higher than those in wheat. As the growth stage proceeding , the nitrate contents in Chinese cabbage and spinach increased, while those in wheat decreased. The nitrate contents of the roots of the 3 crops in the former stage were higher, and in the later stage were lower than those of the stems. The nitrate contents in the stems were higher than in leaves, in petioles (wheat sheaths) higher than in blades. In reproductive organs, the shells of the two vegetables concentrated a great amount of nitrate, and no nitrates were found in the husks and awns of the wheat and the seeds of the 3 crops.