ISSN:
1365-3040
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Biology
Notes:
A novel electrochemical technique was developed to enable high-resolution measurements of trans-plasma membrane reductase activity in vivo in growing plant tissue and single cells. Carbon fibre microelectrodes (CFMEs) with a tip diameter of 5 µm were used for electrochemical mapping of the reduction of the external impermeant electron acceptor ferricyanide along the root tip surface of 4-d-old maize seedlings. Ferricyanide reduction was detected in all locations along the first 12 mm of the growing root apex. However, a distinct peak in activity was detected at the proximal end of the elongation zone (1·5–4·5 mm from the apex), where reductase activity was three times greater than in more apical or distal regions. The inhibition of the ferricyanide reduction at all locations along the growing apex, by the vitamin K antagonists warfarin and dicumarol, supports previous data showing that electron transfer by the constitutive trans-plasma membrane reductase is achieved via a quinone shuttle. We demonstrate that in addition to their utility in whole-tissue/-organ studies, CFMEs are sensitive enough to monitor trans-plasma membrane electron transport in single cells.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1046/j.0016-8025.2001.00714.x
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