Electrical control of differentiation in callus natural electric potentials

✍ Scribed by Andrew Goldsworthy; Alberto Lago

• Publisher: Springer
• Year: 1992
• Tongue: English
• Weight: 417 KB
• Volume: 30
• Category: Article
• ISSN: 0167-6857
• DOI: 10.1007/bf00040024

✦ Synopsis

The surface potentials of tobacco and carrot callus have been measured at various stages of differentiation to form shoots or embryoids using non-polarizable silver/silver chloride electrodes in KCl-filled capillaries. Values on de-differentiating media were seldom in excess of 10 mV and never exceeded 15 mV. Transfer of tobacco callus to a medium conducive to shoot-formation resulted in the appearance of sharply defined areas of much higher surface potentials corresponding to the positions of developing vascular nodules (meristemoids). Shoot regeneration always occurred at the boundary of the developing meristemoids, suggesting that a very steep potential gradient within the tissue may be an important feature of organogenesis.

Similar measurements made on carrot callus regenerating embryoids did not show any corresponding high surface potentials in the regions of embryogenesis. It is concluded that the natural electrical conditions in callus undergoing organogenesis are quite different to those during the formation of embryoids. A possible explanation is proposed.