Tobacco Seedlings: Damage by Excessive Nitrogen Lessened by Added Phosphorus

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Science  07 Jan 1966:
Vol. 151, Issue 3706, pp. 106
DOI: 10.1126/science.151.3706.106


Concentrations of nitrogen (as ammonium nitrate) of 50 kilo-grams per hectare and greater are toxic to tobacco seedlings; symptoms are poor growth and white leaves. The leaves have markedly less chlorophylls (especially chlorophyll a) and more carotene and xanthophyll than seedlings grown in media low in nitrogen. These ill eflects are aggravated by short supply of phosphorus; they can be counteracted by more liberal supply of phosphorus.