Electrical signaling, stomatal conductance, ABA and Ethylene content in avocado trees in response to root hypoxia

Abstract

Abbreviations: ABA, abscisic acid; ACC, 1-aminocyclopropane-1-carboxylic acid; AP, Action Potential; ΔV L-S , voltage differences between the base of the stem and the leaf petiole; ΔV l-b , voltage differences between leaf zone and base of the trunk; gs, stomatal conductance; PPF, photosynthetic photon flux; VP, Variation Potential

Electrophysiology of Woody Plants

“…Orders of magnitude of the observed EP variation in those studies were similar to values observed by other authors (Fromm, 2006;Davies, 2006). Electric potential variations observed in avocado trees in response to decreased soil water content have been associated with a decrease in stomata conductance (gs) (Gil et al, 2009), indicating that stomata closure might be induced or at least associated with an electrical signal that travels through the phloem at a speed of 2.4 cm min -1 . Larger changes in electric potential behavior have been detected in response to drought compared to watering.…”

“…In most of our publications, electrical potentials are monitored continuously using own designed nonpolarizable Ag/AgCl microelectrodes inserted into different positions along the trunk; microelectrode characteristics have been reported by Gurovich & Hermosilla (2009), Gil et al (2009, Oyarce & Gurovich (2011), and consist on a 0.35 mm-diameter silver wire (99.99% Ag), chlorated in a solution of HCl 0.1N for 30 s using a differential voltage of 2.5 V, to obtain an Ag/AgCl coating, which is inserted in a stainless steel hypodermic needle, 0.5 mm in diameter, filled with a KCl 3M solution; both needle ends are heat-sealed with polyethylene. Electrodes were inserted into the trunk using a low velocity electric microdriller, with a barbed microreel, penetrating the phloematic and cambium tissue; needle tip was further inserted into the xylematic tissue, 0.5-0.75 cm, by mechanical pressure.…”

“…Plant neurobiology is aimed at establishing the structure of information networks that exist within the plant, which is expressed as responses to environmental stimuli by means of electrochemical signals (Baluška et al, 2004;Trewavas, 2005). These signals seem to complement other plant signals: hydraulic, mechanical, volatile and hormonal, already well documented in plant science (Fromm & Lautner, 2007;Gil et al, 2009;Dziubinska et al, 2003).…”

“…Artificially applied electric potential differentials between plant organs under field conditions may enhance water use efficiency in woody plants, through its controlled influence on stomata conductance and plant internal water flux Jia & Zhang, 2008;Gil et al, 2009;Gurovich, 2009). …”

Enhanced Stomatal Conductance by a Spontaneous Arabidopsis Tetraploid, Me-0, Results from Increased Stomatal Size and Greater Stomatal Aperture

“…The most significant gene sets, which were enriched in up-regulated genes, were related to plant-type cell wall loosening, an essential step in guard cell swelling (Wei et al, 2011). In down-regulated genes, there were several significant gene sets related to the defense responses for immunity, hypoxia, and ozone, which also influence stomatal responses or gas exchange (Heath, 1994;Melotto et al, 2006;Gil et al, 2009). Microarray analysis demonstrated that these gene expression differences may be related to the differences in stomatal aperture between Me-0 and tetraploid Col evaluated in Figure 3.…”