Annual fluctuation in amplitudes of daily variations of electrical signals measured in the trunk of a standing tree

Koppán, András; Szarka, László; Wesztergom, Viktor

doi:10.1016/s0764-4469(00)00179-7

Cited by 23 publications

(8 citation statements)

References 5 publications

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“…In addition to correctly predicting the trends and magnitudes of the measured voltages between xylem and soil, our proposed mechanism accounts for the variability of voltage between different soils and tree types as well as the observed differences between the same type tree growing in different pH soils. The small alternating fluctuations with periods in the 12 hour range as reported by other groups [5], [12], [13] may still be related to transpiration effects but are unlikely to be due to a streaming potential related mechanism because of the exactly negative correlation they exhibit in some of these reports [12], [13]. According to our measurements, the bulk of the voltage follows a difference in pH rather than any more intricate effects.…”

Section: Discussionsupporting

confidence: 77%

Source of Sustained Voltage Difference between the Xylem of a Potted Ficus benjamina Tree and Its Soil

2008

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It has long been known that there is a sustained electrical potential (voltage) difference between the xylem of many plants and their surrounding soil, but the mechanism behind this voltage has remained controversial. After eliminating any extraneous capacitive or inductive couplings and ground-mediated electric current flows, we have measured sustained differences of 50–200 mV between the xylem region of a Faraday-caged, intact, potted Ficus benjamina tree and its soil, as well as between its cut branches and soils and ionic solutions standardized to various pH values. Using identical platinum electrodes, no correlation between the voltage and time of day, illumination, sap flow, electrode elevation, or ionic composition of soil was found, suggesting no direct connection to simple dissimilar-metal redox reactions or transpirational activity. Instead, a clear relationship between the voltage polarity and magnitude and the pH difference between xylem and soil was observed. We attribute these sustained voltages to a biological concentration cell likely set up by the homeostatic mechanisms of the tree. Potential applications of this finding are briefly explored.

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Section: Discussionsupporting

confidence: 77%

Source of Sustained Voltage Difference between the Xylem of a Potted Ficus benjamina Tree and Its Soil

2008

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“…Results in previous studies are from measurements within a single poplar tree (Fensom, 1963), a single chestnut tree (Morat et al, 1994) and a single oak tree (Koppan et al, 2000(Koppan et al, , 2002. Daily variations relate to the simultaneous sap flow during light hours.…”

Section: Discussionmentioning

confidence: 99%

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

Gurovich

Hermosilla

2009

Journal of Plant Physiology

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“…By measuring the water transport in tree trunks using an Electrical Potential Difference (EPD) technique, near Sopron, Hungary, Koppán et al (2000) found a diurnal fluctuation in xylem-sapflow intensity. The resulting EPD time series parallel the streamflow diel signal (Gribovszki, 2004).…”

Section: Historical Overviewmentioning

confidence: 99%

Diurnal fluctuations in shallow groundwater levels and streamflow rates and their interpretation – A review

Gribovszki

Szilágyi

Kalicz

2010

Journal of Hydrology

219

146

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Diurnal fluctuations of hydrological variables (e.g., shallow groundwater level or streamflow rate) are comparatively rarely investigated in the hydrologic literature although these short-term fluctuations may incorporate useful information for the characterization of hydro-ecological systems. The fluctuations can be induced by several factors like (a) alternating processes of freezing and thawing; (b) early afternoon rainfall events in the tropics; (c) changes in streambed hydraulic conductivity triggered by temperature variations, and; (d) diurnal cycle of water uptake by the vegetation. In temperate climates, one of the most important diurnal fluctuation-inducing factors is the water consumption of vegetation, therefore a detailed overview is provided on the history of such research. Beside a systematic categorization of the relevant historical studies, models that calculate groundwater evapotranspiration from diurnal fluctuations of groundwater level and/or streamflow rate have been reviewed. Compared to traditional evapotranspiration estimation methods these approaches may excel in that they generally employ a small number of parameters and/or variables to measure, are typically simple to use, and yet can yield results even on a short timescale (i.e., hours). While, e.g., temperature-based methods of evapotranspiration are simple too, they cannot be applied or become inaccurate over shorter time periods. Similarly, traditional approaches (such as eddy-correlation or Bowen-ratio based) are accurate for shorter time steps but they require a number of measurable atmospheric input variables.

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Annual fluctuation in amplitudes of daily variations of electrical signals measured in the trunk of a standing tree

Cited by 23 publications

References 5 publications

Source of Sustained Voltage Difference between the Xylem of a Potted Ficus benjamina Tree and Its Soil

Source of Sustained Voltage Difference between the Xylem of a Potted Ficus benjamina Tree and Its Soil

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

Diurnal fluctuations in shallow groundwater levels and streamflow rates and their interpretation – A review

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