Electrophysiology and Phototropism - Communication in Plants: Neuronal Aspects of Plant Life - page 361

Fig. 24.5. Action potentials in a soybean plant induced by changing the direction of white
light irradiation from direction A to direction B as shown in Fig. 24.1. The irradiance was
10 mE m 2 s. The distance between electrodes was 5 cm. The soil was preliminarily treated

with water every day. The volume of soil was 0.5 L. The frequency of scanning was 50,000
samples/s

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of the electrochemical responses undergo changes. From the theoretical
perspective, the changes in the shapes and wave speeds of the traveling
waves can be accounted for by appropriate changes in the parameters in
the corresponding nonlinear differential equations (Volkov and Mwesigva
2001a).
Hodgkin and Huxley's membrane model accounts for K + ,Na + , and ion-
leakage channels in squid giant axons (Fig. 24.8a). The membrane resting
potential for each ion species is treated like a battery and a variable resistor
modelsthedegreetowhichthechannelisopen.
Fromm and Spanswick (1993) discovered that the electrical stimula-
tion of the plant is followed by ion shifts, which are most striking in