This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via CrossRef Citing Articles via Web of Science (47) Citing Articles via Google Scholar Google Scholar Articles by Radin, J. W. Search for Related Content PubMed PubMed Citation Articles by Radin, J. W. Agricola Articles by Radin, J. W.

Articles

Distribution and Development of Nitrate Reductase Activity in Germinating Cotton Seedlings ¹

^a Western Cotton Research Laboratory, Agricultural Research Service, United States Department of Agriculture, Phoenix, Arizona 85040

Activity of nitrate reductase in roots and cotyledons of cotton seedings (Gossypium hirsutum L. cv. Deltapine 16) increased rapidly on germination, reaching a maximum after 1 day of imbibition. Thereafter, activity declined until emergence and greening of the cotyledons, when it again began to increase steadily. Germinating soybean (Glycine max (L.) Merrill cv. Merit) and sunflower (Helianthus annuus L. cv. Peredovic) seedlings did not show the early peak of activity. The early peak depended on nitrate and was sensitive to cycloheximide, but not to actinomycin D or other inhibitors of RNA synthesis. The second, light-dependent increase was sensitive to actinomycin D. In roots, the early peak of activity occurred before any growth. After emergence of the root tip from the seed coat, activity was localized in the terminal 2 millimeters, whether expressed on a fresh weight, protein, or root basis. The difference in activity between the apical (0-2 millimeter) and subapical (2-4 millimeter) segments did not result from differences in nitrate availability, energy supply, or turnover rates of nitrate reductase. Root activity was similar to that of the cotyledons after emergence, in that both were sensitive to actinomycin D.

This article has been cited by other articles:

				D. Loque, P. Tillard, A. Gojon, and M. Lepetit Gene Expression of the NO3- Transporter NRT1.1 and the Nitrate Reductase NIA1 Is Repressed in Arabidopsis Roots by NO2-, the Product of NO3- Reduction Plant Physiology, June 1, 2003; 132(2): 958 - 967. [Abstract] [Full Text] [PDF]