Hydro-Electrochemical Integration of the Higher Plant – Basis for Electrogenic Flower Induction - Communication in Plants: Neuronal Aspects of Plant Life - page 385

be detected shortly after a light-dark or a dark-light transition (Wagner et
al 1998). Measurements under the non-inductive light conditions for flow-
ering did show that in the long-day plant C. murale mainly light-on signals
were observed, while in the short-day plant C. rubrum an accumulation of
the signals was observed after the light-dark transition. Under the influ-
ence of the flower-inducing photoperiods, both groups of plants showed an
inverse pattern of action potential accumulation. In long-term measure-
ments, the correlation between flower induction and the classification of
action potentials either as light-on or as light-off signals could clearly be
demonstrated. Therefore, this criterion is an important indicator for the
state of flowering or for the differentiation between long- and short-day
plant material. Thus, it has been shown that short-day plants and long-day
plants each display characteristic distributions of action potentials during
dark and light phases, which are characteristic for flower-inducing and
non-flower-inducing conditions. It follows that the temporal distribution
of action potentials over and within dark and light spans can also be reliably
used as a marker for the flowering state of a given plant material (Wagner
et al. 2004).
25.8
Substitution of Photoperiodic Flower Induction
by Electrogenic Flower Induction
Specific electrophysiograms characteristic for photoperiodic flower induc-
tion were generated providing information concerning the electrical signal
patterns of flower-induced plants. Experiments on electrostimulation using
specific impulse patterns of DC current were aimed at inducing flowering
under non-inductive light conditions. The results obtained showed that
DC pulses during a fixed period of time for 1.5 h on seven consecutive days
clearly induced seven of the 12 plants under investigation. With inverse
polarity of the stimulating DC current, the apices of the stimulated plants
did not show any difference compared to the apices of non-stimulated
control plants (Wagner et al. 2004). These results clearly show that the ad-
equate polarity of the stimulating electrodes is of decisive importance for
flower induction. The temporal patterns of the stimulating currents should
be selected depending on the type of plant (short-day or long-day) and
the temporal pattern of the transition between endogenous oscillation in
photophile and skotophile phases. The results obtained prove that flower
induction in the plant can be induced by electrophysiological stimulation
under non-flower-inducing environmental conditions.