The influence of small direct electric currents on the transport of auxin in intact plants

✍ Scribed by D. A. Morris

• Publisher: Springer-Verlag
• Year: 1980
• Tongue: English
• Weight: 399 KB
• Volume: 150
• Category: Article
• ISSN: 0032-0935
• DOI: 10.1007/bf00390181

✦ Synopsis

When a d.c. potential of 9.0 V was applied to the stem of intact pea seedlings (Pisum sativum L. cv. Meteor and cv. Alderman) via 10 mM KC1soaked filter paper electrodes placed ca. 50 m m apart the stem passed a steady current of 15-20 ~tA (resistance ca. 100 kf~ cm *). The basipetal transport of [1-1~C]IAA applied to the apical bud was completely inhibited over the portion of the stem through which current flowed and 14C-labelled compounds accumulated in the vicinity of the upper electrode. The inhibition of transport was independent of the polarity of the applied potential. The basipetal transport of IAA in the stern above the electrode was not affected.

Labelled auxin accumulated at the upper electrode both as unchanged IAA and as a compound tentatively identified as indol-3yl-acetyl aspartic acid (IAAsp). These compounds were only slowly remobilised when the current was interrupted. However, the ability of the transport system to move freshly-applied IAA was rapidly and fully restored when the potential was removed. No injury to the plant was detected after maintaining a current flow for up to 72 h. No leakage of a4C-labelled compounds into the KC1 solution bathing the electrodes was detected.