Nitrate reductase activity (NRA) in leaf blades was 27 and 9 times higher than that in petioles and roots, respectively.Leaf blade was the main organ responsible for the reduction of nitrate.

• 叶片硝酸还原酶活性分别是叶柄和根系的27和9倍，呈现叶片＞根系＞叶柄，叶片是硝态氮的主要还原器官。