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Plant Physiology 61:900-903 (1978) © 1978 American Society of Plant Biologists Sulfur Deprivation and Nitrogen Metabolism in Maize Seedlings 1Department of Agronomy, University of Wisconsin, Madison, Wisconsin 53706
The objective of this experiment was to elucidate the manner in which N metabolism is influenced by S nutrition. Maize (Zea mays L.) seedlings supplied with Hoagland solution minus SO42 exhibited S deficiency symptoms 12 days after emergence. Prior to development of these symptoms, a decline in leaf blade nitrate reductase (NR, EC 1.6.6.1) activity was observed in S-deprived seedlings compared to normal seedlings. Twelve days after emergence, in vitro NR activity was diminished 50% compared to normal seedlings. Glutamine synthetase (EC 6.3.1.2) and NAD-glutamate dehydrogenase (EC 1.4.1.2) activities were less severely affected (19 and 13%, respectively, at day 12). NADP-glutamate dehydrogenase (EC 1.4.1.4) activity and leaf blade fresh weight were not altered by S deprivation. Concentrations of soluble protein and chlorophyll (a and b) in leaf blades were reduced 18 and 25%, respectively, at day 12. A significantly higher concentration of NO3-N was observed for leaf blade and stem (culms, leaf sheaths, and unfurled leaves) fractions (46 and 31%, respectively) in S-deprived plants. In contrast to the other parameters measured, NR activity in S-deprived seedlings could be readily restored to the normal level by addition of SO42. The apparent preferential effect of S deprivation on NR activity could be causally related to the observed changes in NO3-N and soluble protein concentration.
1 Research supported by College of Agricultural and Life Sciences, University of Wisconsin-Madison. Research conducted by J.W.F. in partial fulfillment of requirements for the Ph.D. degree at UW-Madison. This article has been cited by other articles:
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