Electrical phenomena in plants have attracted scientists since the eighteenth century.
Similar to animal cells, also plant cells possess the ability to become excited under the influence of certain environmental factors and to generate rapid electrical signals propagating over long distances. The reason why plants have developed pathways for fast signal transmission presumably lies in the necessity to rapidly respond to environmental stress factors.
Jörg Fromm and colleagues from the University of Hamburg here show that maize plants generate electrical signals in the phloem, that is, the inner layer of the bark, after cold shock as well as wounding of a leaf tip. Interestingly, the signal induced by cold shock travels rapidly with up to 3 cm per second towards the middle of the leaf to reduce assimilate transport within the phloem and the neighboring leaf cells, and to trigger the synthesis of carbohydrates like starch and callose.
In contrast, wound-induced signals have a different shape, a speed of only 0.5 cm per second, and do not inhibit assimilate translocation but reduce photosynthesis and the amount of almost all metabolites in the leaf.
Fromm and colleagues conclude that different environmental factors such as cold shock and wounding incite characteristic electrical signals, each with a specific influence on photosynthesis, assimilate transport and biochemistry.
URL: http://www.frontiersin.org/Plant_Physiology/10.3389/fpls.2013.00239/abstract