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plant_perception [2012-10-17 10:41] – nik | plant_perception [2012-10-18 07:46] – nik |
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====Plant Perception==== | ====Plant Perception==== |
see [[WP>Plant_perception_(physiology)]] (or [[WP>Plant_perception_(paranormal)]])wrt. [[HPI]] | see [[WP>Plant_perception_(physiology)]] (or [[WP>Plant_perception_(paranormal)]]) wrt. [[HPI]] |
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=== light & elctrochemical responses === | === light & elctrochemical responses === |
"surface measurements appear better suited as they are non-invasive and physically stable; they may also be performed simultaneously with other physiological methods such as gas exchange recordings (Fromm & Fei 1998). Such electrodes usually consist of Ag/AgCl wire, moistened with 0.1% (w/v) KCl in agar and wrapped in cotton to provide the appropriate contact with the plant surface (Fromm & Spanswick 1993), or of Ag/AgCl pelleted electrodes that can be connected to the plant surface by means of a conductive aqueous gel of the type commonly used in ECG (Mancuso 1999). At different positions of a plant surface, electrodes can be connected by screened cables to a high-input impedance electrometer with many channels. An identical electrode can either be placed on the distal region of a plant or in the soil to serve as a reference electrode (Fig. 1a). When all channels show stabilized potentials, the plant can be stimulated electrically at the apex (e.g. 3 V for 2 s) or by other stimuli (flaming, cold shock) applied to a leaf. Usually, the electrical responses to an apical stimulus can be shown by all electrodes, from top to bottom of the plant (Fig. 1a), indicating that the trans- mission of an electrical signal is occurring throughout the plant. For example, a similar experimental set-up has been used in sunflower to analyse the characteristics of APs and VPs (Stankovic et al. 1998)." | "surface measurements appear better suited as they are non-invasive and physically stable; they may also be performed simultaneously with other physiological methods such as gas exchange recordings (Fromm & Fei 1998). Such electrodes usually consist of Ag/AgCl wire, moistened with 0.1% (w/v) KCl in agar and wrapped in cotton to provide the appropriate contact with the plant surface (Fromm & Spanswick 1993), or of Ag/AgCl pelleted electrodes that can be connected to the plant surface by means of a conductive aqueous gel of the type commonly used in ECG (Mancuso 1999). At different positions of a plant surface, electrodes can be connected by screened cables to a high-input impedance electrometer with many channels. An identical electrode can either be placed on the distal region of a plant or in the soil to serve as a reference electrode (Fig. 1a). When all channels show stabilized potentials, the plant can be stimulated electrically at the apex (e.g. 3 V for 2 s) or by other stimuli (flaming, cold shock) applied to a leaf. Usually, the electrical responses to an apical stimulus can be shown by all electrodes, from top to bottom of the plant (Fig. 1a), indicating that the trans- mission of an electrical signal is occurring throughout the plant. For example, a similar experimental set-up has been used in sunflower to analyse the characteristics of APs and VPs (Stankovic et al. 1998)." |
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| "Environmental stimuli such as spontaneous changes in temperature, light, touch or wounding can induce electrical signals at any site of the symplastic continuum." |
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| == signal types == |
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| Action Potential (AP) - rapidly propogating fixed amplitude signals, triggered with stimulus at threshold, do not vary with singal intensity, passivly propogating. signal duration/propogation in the order of seconds, with refractory periods in the order of 10s of seconds or minutes in some plants. amplitudes in the order of 100mV in mimosa. |
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| Variation Potential (VP) - also refered to as 'slow wave potentials'. continuous, varying amplitude in relation to stimululus, non-self perpetualting, singal duration in the order of minutes, amplitude in similar range to APs, amplitude and speed of signals can decrease from the site of local stimulus. |
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=== misc & various === | === misc & various === |