缺氮植物表现出上述的许多症状。
Nitrogen-deficient plants exhibit many of the symptoms just described.
许多植物中，轻度缺氮在其发育的某些阶段可能是适宜的。
In some plants, a mild nitrogen deficiency at certain stages of development may be desirable.
在19世纪晚期，科学家断定，缺氮将成为一个全球性的问题。
In the late 19th century scientists diagnosed a shortage of nitrogen as a planet-wide problem.
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