Skip Navigation

This Article
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Alert me to new issues of the journal
Right arrow Add to My Personal Archive
Right arrow Download to citation manager
Right arrowRequest Permissions
Google Scholar
Right arrow Articles by Ichino, K.
Right arrow Articles by Okamoto, H.
Right arrow Search for Related Content
PubMed
Right arrow Articles by Ichino, K.
Right arrow Articles by Okamoto, H.
Agricola
Right arrow Articles by Ichino, K.
Right arrow Articles by Okamoto, H.
Social Bookmarking
Add to CiteULike   Add to Connotea   Add to Del.icio.us  
What's this?

Plant and Cell Physiology, 1973, Vol. 14, No. 1 127-137
© 1973

Article

Distribution of electric potential and ion transport in the hypocotyl of Vigna sesquipedalis II. Axial potential difference

Kazuo Ichino, Kiyoshi Katou and Hisashi Okamoto

Biological Institute, Faculty of Science, Nagoya University Nagoya, Japan

Vital staining with pH indicator dyes made it possible to identify the xylem with the specific channel A, reported previously, through which hydrogen ions flow generating a resting potential difference along the germ axis as their diffusion potential. The distribution of K+ concentration within this channel showed no similarity to electric potential distribution, in contrast to the distribution of H+.

The axial P.D. between both ends of a segment cut from a hypocotyl responded reversibly to the change in O2 tension of the surrounding gas phase. After air had been quickly replaced by N2, a lag period appeared before the sudden potential drop took place. The lag period ({tau}) was largely dependent on temperature. Apparent activation energy of the process characterized by 1/{tau} was 18 Kcal/mole between 14–30°C, approximately equal to that of the O2-uptake within the same temperature range. The relation between O2 concentration and the maximum rate of recovery of P.D. from anoxia was of the Michaelis-Menten type; the apparent Km was calculated as 2.1 × 10–5M O2 being of the same order as that of cytochrome oxidase in higher plants. The O2-uptake rate "per unit of hypocotyl length" showed a distinct maximum in the elongating region where the axial distribution of both electric potential and pH within channel A had their minimums.

(Received July 21, 1972; )
Add to CiteULike CiteULike   Add to Connotea Connotea   Add to Del.icio.us Del.icio.us    What's this?




Disclaimer:
Please note that abstracts for content published before 1996 were created through digital scanning and may therefore not exactly replicate the text of the original print issues. All efforts have been made to ensure accuracy, but the Publisher will not be held responsible for any remaining inaccuracies. If you require any further clarification, please contact our Customer Services Department.