Transient knockout of photosynthesis mediated by electrical signals.

•  In the sensitive species Mimosa pudica electric signals arise when the leaves are stimulated by touching or wounding. Experiments reported here provide information about a photosynthetic response that results from heat-induced electrical signalling in leaves. •  Electric potential measurements, combined with chlorophyll fluorescence, as well as gas exchange measurements showed that wounding evokes an electrical signal that travels rapidly into the neighbouring leaf pinna to eliminate the net-CO2 uptake rate. At the same time the PSII quantum yield of electron transport is reduced from c. 0.6 to 0.2. Two-dimensional imaging analysis of the chlorophyll fluorescence signal revealed that the yield reduction spreads acropetally through the pinna and via the veins through the leaflets. •  To determine the speed of a chemical signal, a part of a pinna was exposed to 14 CO2 . The remaining parts of the leaf were provided with label only when the translocation was extended to 12 h, indicating that a chemical signal is much too slow to account for the photosynthetic response after heat stimulation. •  The results provide evidence for a role of the electrical signal in the regulation of photosynthesis because the high speed of the signal transduction rules out the involvement of a chemical signal, and the photosynthetic response occurs after the arrival of the electrical signal in the leaf pinna.

[1]  A. Bulychev,et al.  Electro-induced changes of chlorophyll fluorescence in individual intact chloroplasts , 1986 .

[2]  K. Umrath.  Über die Erregungsleitung bei sensitiven Pflanzen, mit Bemerkungen zur Theorie der Erregungsleitung und der elektrischen Erregbarkeit im allgemeinen , 1928, Planta.

[3]  J. Fromm,et al.  Control of phloem unloading by action potentials in Mimosa , 1991 .

[4]  Jörg Fromm,et al.  Transport processes in stimulated and non-stimulated leaves of Mimosa pudica , 1988, Trees.

[5]  M. Hütt,et al.  Spatiotemporal variation of metabolism in a plant circadian rhythm: The biological clock as an assembly of coupled individual oscillators , 2001, Proceedings of the National Academy of Sciences of the United States of America.

[6]  M. Tyree,et al.  The symplast concept. A general theory of symplastic transport according to the thermodynamics of irreversible processes. , 1970, Journal of theoretical biology.

[7]  P. A. Anderson,et al.  Epithelial conduction: Its properties and functions , 1980, Progress in Neurobiology.

[8]  Eric Davies,et al.  Action potentials as multifunctional signals in plants: a unifying hypothesis to explain apparently disparate wound responses , 1987 .

[9]  G. Mackie.  CONDUCTION IN THE NERVE-FREE EPITHELIA OF SIPHONOPHORES. , 1965, American zoologist.

[10]  J. C. Bose,et al.  The Nervous Mechanism of Plants , 1926, Nature.

[11]  J. Briantais,et al.  The relationship between the quantum yield of photosynthetic electron transport and quenching of chlorophyll fluorescence , 1989 .

[12]  R. W. Snow.  Conduction of Excitation in Stem and Leaf of Mimosa pudica , 1924 .

[13]  C. Ryan.  Protease Inhibitors in Plants: Genes for Improving Defenses Against Insects and Pathogens , 1990 .

[14]  M. Saltveit,et al.  Rapidly Induced Wound Ethylene from Excised Segments of Etiolated Pisum sativum L., cv. Alaska: I. Characterization of the Response. , 1978, Plant physiology.

[15]  D. Dilley.  Rapidly Induced WoundEthylene fromExcised Segments of Etiolated Pisumsativum L., cv.Alaska , 1978 .

[16]  T. Sibaoka.  Action potentials in plant organs. , 1966, Symposia of the Society for Experimental Biology.

[17]  D. Gradmann,et al.  Laser-Interferometric Re-examination of Rapid Conductance of Excitation in Mimosa pudica , 1990 .

[18]  H. Schildknecht.  Turgorins, Hormones of the Endogeneous Daily Rhythms of Higher Organized Plants—Detection, Isolation, Structure, Synthesis, and Activity , 1983 .

[19]  Takashi Shiina,et al.  Action Potential in Luffa cylindlica and its Effects on Elongation Growth , 1986 .

[20]  H. Schildknecht,et al.  Aminosäuren als „leaf movement factors” , 1978, Naturwissenschaften.

[21]  T. Sibaoka,et al.  Physiology of Rapid Movements in Higher Plants , 1969 .

[22]  M. Malone.  Kinetics of wound-induced hydraulic signals and variation potentials in wheat seedlings , 1992, Planta.

[23]  K. Siebke,et al.  Assimilation images of leaves of Glechoma hederacea: Analysis of non-synchronous stomata related oscillations , 1995, Planta.

[24]  W. Bilger,et al.  Continuous recording of photochemical and non-photochemical chlorophyll fluorescence quenching with a new type of modulation fluorometer , 2004, Photosynthesis Research.

[25]  Jörg Fromm,et al.  Electric Signals Released from Roots of Willow (Salix viminalis L.) Change Transpiration and Photosynthesis , 1993 .

[26]  J. B. Hanson,et al.  Sensitivity of the proton and ion transport mechanisms of corn roots to injury , 1980 .

[27]  M. Saltveit,et al.  Rapidly Induced Wound Ethylene from Excised Segments of Etiolated Pisum sativum L., cv. Alaska: II. Oxygen and Temperature Dependency. , 1978, Plant physiology.

[28]  A. L. Houwink,et al.  The conduction of excitation in Mimosa pudica , 1935 .

[29]  J. Snel,et al.  The use of chlorophyll fluorescence nomenclature in plant stress physiology , 1990, Photosynthesis Research.

[30]  P. Minchin,et al.  Electrical signalling and systemic proteinase inhibitor induction in the wounded plant , 1992, Nature.

[31]  J. Fisahn,et al.  Effects of mechanical wounding, current application and heat treatment on chlorophyll fluorescence and pigment composition in tomato plants , 1999 .

[32]  D. Bowles,et al.  Defense-related proteins in higher plants. , 1990, Annual review of biochemistry.

[33]  H. Dziubińska,et al.  The effect of excitation on the rate of respiration in the liverwort Conocephalum conicum , 1989 .

[34]  M. Filek,et al.  The effect of wounding the roots by high temperature on the respiration rate of the shoot and propagation of electric signal in horse bean seedlings (Vicia faba L. minor) , 1997 .

[35]  W. Ruhland.  Encyclopedia of plant physiology. , 1958 .

[36]  B. Thomas,et al.  The Control of Wound Callose Formation in Willow Phloem , 1979 .