Electric signalling in fruit trees in response to water applications and light–darkness conditions

A non-invasive plant-based probe for continuous monitoring of water stress in real time: a new tool for irrigation scheduling and deeper insight into drought and salinity stress physiology

“…The probes are non-invasive and therefore very robust in comparison to all other minimal-invasive technologies used or suggested for irrigation. These techniques require the insertion of microcapillaries and/or electrodes , Fernández et al 2001, Nadler et al 2003, Zimmermann et al 2004, Gurovich and Hermosilla 2009. Even though minimal-invasive techniques have a high impact for basic research, they are not suitable for outdoor measurements.…”

“…For example, Wegner and Zimmermann (1998; see also review article of Zimmermann et al 2004) using the miniaturised xylem pressure-potential probe have demonstrated for wheat and maize (Zea mays) that the xylem and turgor pressure changes induce synchronous changes in the transroot electrical potential, presumably due to electrokinetic effects on the cell/tissue level close to the xylem. Electric potential changes have also been detected recently between the base of the stem and upper leaf of avocado trees (Persea americana) in response to drought, irrigation and diurnal light/dark regimes (Fromm 2006, Davies 2006, Gurovich and Hermosilla 2009). Gurovich and others discuss propagation of the electric signals through the tree, but ignore that pressure propagation through the xylem vessels and tissue is most likely the primary event that leads subsequently to electrical changes on the cellular level (see also Westhoff et al 2008Westhoff et al , 2009b.…”

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

“…For each treatment, five single-plant replications were randomly placed in a Faraday cage to prevent external electromagnetic signals in the greenhouse from interfering with the long-term experiment, diurnal cycles of electrical potential were observed that were most likely related to light and vapor pressure deficit (VPD) conditions. 29,30 Therefore, we analyzed the voltage difference between the data collected at midday on the last day of the treatment period and the initial voltage value recorded at the moment that treatments were initiated.…”

Electrophysiology of Woody Plants

“…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.…”

“…In fruit bearing deciduous and perennial plant species, electrophysiology studies are very limited as well, although it is in such plants that the need for rapid and efficient signals other than chemical and hydraulic signaling becomes more obvious Nadler et al 2008;Gurovich & Hermosilla, 2009;Oyarce & Gurovich, 2011). These studies have associated the effect of water stress, deficit irrigation, light cycles and mechanical or heat injury with electrical signaling in several fruit bearing tree species.…”