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N Deprivation in Maize During Grain‐Filling. I. Accumulation of Dry Matter, Nitrate‐N, and Sulfate‐S 1
Author(s) -
Friedrich J. W.,
Schrader L. E.,
Nordheim E. V.
Publication year - 1979
Publication title -
agronomy journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.752
H-Index - 131
eISSN - 1435-0645
pISSN - 0002-1962
DOI - 10.2134/agronj1979.00021962007100030020x
Subject(s) - dry matter , agronomy , nutrient , nitrate , dry weight , zea mays , poaceae , nitrogen , chemistry , biology , horticulture , zoology , organic chemistry
Maize ( Zea mays L.) has a noted propensity for accumulating large amounts of nitrate‐N (NO 3 ‐N). However, the availability of such NO 3 ‐N for assimilation during periods of restricted N supply has not been assessed. In addition, the availability of sulfate‐S (SO 4 ‐S) affects the accumulation and assimilation of NO 3 ‐N. Little is known about the effect of NO 3 ‐N supply on SO 4 ‐S accumulation. Such information is vital to efforts to improve the efficiency of nutrient utilization by crops. The objective of this greenhouse experiment was to determine the effect of N deprivation during grain‐filling on the accumulation of dry matter, NO 3 ‐N, and SO 4 ‐S. Maize plants were grown hydroponically in a modified Hoagland's solution. At silking the nutrient solution was replaced with fresh solution, with or without NO 3 ‐N. Plants were harvested and separated into seven fractions at silking and 1, 2, 3, 5, and 7 weeks after silking. Plants that were supplied NO 3 ‐N during grain‐filling contained almost twice (1.8×) as much N at physiological maturity (7 weeks after silking) as did N‐deprived plants. Ear dry weight was not affected by N deprivation. The concentration of NO 3 ‐N in all fractions declined during grain‐filling; however, N deprivation enhanced this decline in the roots, lower stem, and upper stem. Lack of N did not affect NO 3 ‐N concentration in the lower leaves, upper leaves, or ear. The concentration of SO 4 ‐S in the roots nearly doubled between silking and physiological maturity when plants were deprived of NO 3 ‐N, but did not change when N was supplied. The concentration of SO 4 ‐S in all other parts was not markedly affected by N deprivation. Apparently, maize plants can compensate for a restricted N supply during grain‐filling by utilizing NO 3 ‐N stored in the roots and stem.