Full Text
(53 K)

Metabolic Regulation of Nitrate Efflux and Net Uptake in Acala and Pima Cotton

Robert L. Travis, M. Aslam, F. Fritschi and D. W. Rains


The effect of temperature and several metabolic inhibitors on NO3- fluxes in intact roots of 8-day-old seedlings of Pima (S-7) (Gossypium Barbadense L.) and Acala (Maxxa) (Gossypium hirsutum L.) cotton was studied. Fluxes were induced with 0.1 mM NO2- (influx) or 0.1 mM NO3- (net uptake and efflux) for 24 h. Absorption (influx and net uptake) and efflux, respectively, were determined by following NO3- depletion from, and accumulation in, the external solution. Both NO3- uptake and efflux were sensitive to temperature extremes. Net NO3- uptake decreased both at lower and higher temperatures, whereas efflux was stimulated. Azide and arsenate inhibited net NO3- uptake; however, arsenate had no effect on efflux, while azide stimulated that system. Thus, azide had a greater inhibitory effect on net uptake than on influx. Dinitrophenol also inhibited net NO3- uptake and influx and had little effect on efflux. Carbonyl-m-chlorophenyl hydrazone and diethylstilbestrol inhibited net uptake and stimulated efflux. The responses of the metabolic modifiers were similar in both Pima and Acala cotton.

Reprinted from Proceedings of the 1998 Beltwide Cotton Conferences pp. 1469 - 1472
©National Cotton Council, Memphis TN

[Main TOC] | [TOC] | [TOC by Section] | [Search] | [Help]
Previous Page [Previous] [Next] Next Page
Document last modified Sunday, Dec 6 1998