title: Biophoton emission of a lichen species Parmelia tinctorum.
abstract: The properties of biophoton signals emitted by samples of lichen species P. tinctorum are investigated. The shape of a light induced signal is determined from 5 ms onwards using successively the bin resolution of 1, 10 and 100 ms; 1000 measurements in successive bins are made at each resolution. The measurement of the shape is repeated at various temperatures in the range (1 degree-40 degrees C) in steps of 1 degree C. It is found that a biophoton signal is very sensitive to temperature and different portions of the signal show different sensitivity. The temperature dependence of the decaying part is even qualitatively different from that of the non-decaying part. The signal responds to temperature changes of 0.1 degrees C in less than 1 ms. The effect of monochromatic stimulation on the strengths of the signal and its red, blue and green spectral components are determined in the wavelength range (400-700) nm in steps of 10 nm. The signal and its broad spectral components have similar excitation curves. The relative strength of spectral component appears independent of the stimulating wavelength. The shape of the decaying portion of the signal and its red, blue and green components is also determined. The character of decay in all four cases is non-exponential. The measurements with various interference filters spanning the entire visible region are made with the bin size of 20 s. These measurements are qualitative because of large fluctuations but suggest that the spectral components of a biophoton signal are distributed in the entire visible region. The probabilities of detecting different number of photons in the non-decaying portion are determined by making 30,000 measurements in each set with the bin size of 50, 100, 200, 300, 400, 500 and 700 ms. The probabilities determine the parameters of a squeezed state of light--the magnitude of its displacement parameter is different but the phase of its displacement parameter and its squeezing parameter are same for different sizes of a bin. These measurements further indicate that the average signal strength remains constant for 19 hr.
authors.affiliation: Institute of Self Organising Systems and Biophysics, North Eastern Hill University, Shillong 793022, India. rpbajpai@nehu.ac.in
authors.forename: R P
authors.initials: RP
authors.lastname: Bajpai
mesh_terms: D008011:Lichens / Q000502:physiology*; D017785:Photons