SHORT COMMUNICATION Coincidence of biophoton emission by wheat seedlings during simultaneous, transcontinental germination tests Cristiano M. Gallep & Thiago A. Moraes & Samuel R. dos Santos & Peter W. Barlow Received: 10 May 2012 / Accepted: 7 August 2012 # Springer-Verlag 2012 Abstract Measurements of spontaneous ultra-weak light (biophoton) emission from native Brazilian and German wheat seedlings in three simultaneous series of germination tests are presented, two run in Germany and one in Brazil. Seedlings in both countries presented semi-circadian rhythms of emission that were in accordance with the local lunisolar gravimetric tidal acceleration, as did seeds which had been transported from Brazil to Germany. The simulta- neity of the photon emission patterns in all tests argues for the lunisolar tide and its rhythmic variations as regulators of the natural rhythm of photon emission. However, seedlings from seed samples transported from Brazil to Germany showed, in addition, a temporary disturbance within the emission periodicity which may indicate a possible short- term acclimatization to the new location. Keywords Biophoton emission . Chronobiology . Germination . Gravimetric tides . Wheat It was recently shown that the naturally occurring, sponta- neous ultra-weak photon emissions from wheat seedlings present circadian and semi-circadian rhythms—i.e., perio- dicities of around 12 and 24 h—in synchrony with the temporal pattern of variations of local gravimetric tidal acceleration (Moraes et al. 2012) due to the locally varying influence of sun and moon upon the gravitational field of the Earth. This spontaneous biophoton emission is an indicator of organism metabolism and viability and can be used as a noninvasive, real-time probe of the living state (Devaraj et al. 1997, Popp 1998). The rhythmic fluctuation of biophoton emissions may also prove to be a useful indicator in chro- nometric studies of other types of biological material (Barlow and Fisahn 2012). Three sets of germination tests simultaneously run in total darkness in Germany (at the International Institute of Biophysics (IIB), Neuss) with both local German (DE) and Brazilian (BR) wheat seeds, and in Brazil (at the University of Campinas, Limeira) with local BR seeds only, were monitored by means of a photon-counting apparatus. A preliminary comparison of their biophoton emission time- courses was already presented by Gallep et al. (2009). Details of experimental procedure and statistical local cor- relation analysis can be checked online, with aid of Figs. A1 to A7. 1 Here, a more detailed analysis of the biophoton emission patterns is presented, using the comparative statis- tical methods of Moraes et al. (2012), with the three time sequences of emissions juxtaposed with the lunisolar-driven gravimetric tidal patterns relevant to the two test sites, one in Germany and the second in Brazil. Comparisons of the fast Fourier transform (FFT) components of the biophoton emis- sion patterns established the rhythmic components in the respective timecourses. Local correlation (Pearson) factor, as well as auto- and cross-correlation functions, was used to study time/frequency similarities, as detailed by Moraes et al. (2012). 1 www.ft.unicamp.br/gallep/Gerais/DEBR.pdf Handling Editor: Peter Nick Electronic supplementary material The online version of this article (doi:10.1007/s00709-012-0447-x) contains supplementary material, which is available to authorized users. C. M. Gallep (*) : T. A. Moraes : S. R. dos Santos School of Technology, University of Campinas, Limeira, SP, Brazil e-mail: gallep@ft.unicamp.br S. R. dos Santos School of Agricultural Engineering, University of Campinas, Campinas, SP, Brazil P. W. Barlow (*) School of Biological Sciences, University of Bristol, Bristol BS8 1UG, UK e-mail: p.w.barlow@bristol.ac.uk Protoplasma DOI 10.1007/s00709-012-0447-x