HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Skogley, E. O. Articles by McCants, C. B. Search for Related Content PubMed Articles by Skogley, E. O. Articles by McCants, C. B. Agricola Articles by Skogley, E. O. Articles by McCants, C. B.

Ammonium Influences on Rubidium Absorption and Distribution by Tobacco Seedlings¹

ABSTRACT

Mechanisms whereby NH₄ influences the accumulation of cations in tobacco were investigated using short-term solution studies with Rb⁸⁶. Measurements on the influence of seedling size and absence of tops on the accumulation of Rb in roots indicated that the size of the plant was positively correlated with Rb accumulation only to the extent of 0.7. During a 6-hour period roots had the major influence on Rb accumulation, the absence of tops making little or no difference. During this absorption period it was found that NH₄ had the same influence as K on the absorption of Rb, while after 24 to 48 hours NH₄, relative to K, had an additional depressive influence on Rb accumulation, especially in the tops of seedlings. The possible involvement of NH₄ influences on transpiration rate and associated passive ion transport was investigated. No NH₄ influence on transpiration was found during periods extending to 70 hours. Salt treatments subsequent to Rb⁸⁶ treatments indicated that the distribution of Rb was dependent more on conditions during its absorption than on those imposed later. Results from these and other studies are used to develop a mechanism for Rb absorption and distribution by tobacco seedlings which accounts for the observed influences of NH₄ on Rb accumulation through an effect on absorption competition and metabolic ion transport.

¹ Contribution from the Department of Soils, North Carolina Agr. Exp. Sta., Raleigh. Published with the approval of the Director as paper No. 1591 of the Journal Series.

² Formerly Graduate Assistant and Associate Professor, respectively.

Received for publication August 8, 1962. Accepted for publication May 8, 1963.