Biophotons - Various
Light generated in living systems used as intercellular communication and other viewpoints
A step back before postulating any relation of biophotons to consciousness or mind is to prove if at least they serve as information signals, this section tend to validate this hypothesis and show other biophoton related utilities like their possible use as a diagnostic tools in medicine. Also some general reviews are included. ...
Biophoton emissions are an endogenous bioluminescence phenomenon, identified in all biological samples. The biophoton origin inside cell is not totally elucidated (see section  or introductory notes of the section ) although some propositions have fairly strong evidence in their favour, most probably various sources are involved. Even though photon density within cells is assumed to be very high  photon emission outside cells is ultra-weak , because of this are also called ultraweak photon emissions (UPE).
Several approaches to the phenomena will be treated in this section, the first approach is relative to the experimental findings that support the idea that biophotonic signals are used as a communication form between distant cells or microorganisms.
Investigations in the area of light-mediated communication among microorganisms has a long history. Namely, it started immediately after the discovery of mitogenetic radiation by Alexander Gurvitch in the 1920s. Those effects were measured at the beginning using only biological systems as a detector, but with the development of photomultipliers these previously inferred emissions began also to be measured electronically, especially from the decade of 1980 onwards, and the scientific literature began to refer them as ultraweak photon emissions or biophotons.
The classical method to infer a signaling role of biophotons is to compare reactions to different stimulus of separated biological samples, a pair of them separated by a barrier that isolates them also electromagnetically and other pair than not have this kind of barrier , in this paper is also referred a example where are correlated chemiluminescence (that is not biophotonic emission, only a chemical reaction with much greater intensity) with a possible biophotonic communication:
" Wonderful experiment indicating communication between chemically isolated populations comes from the protozoan Gonyaulax polyedra (phylum: Dino flagellata) showing the release of irregular bursts of photons of the same frequency (note that we talk here of bioluminescence) (Popp et al., 1994). The study demonstrated that these bursts were caused by a communication system between the cells working across glass barriers. When two populations were placed side-by-side in cuvettes with a photon shield between them, the bursts of each population were asynchronous in comparison with the other population. When the shield was removed, however, the bursts of the two populations became synchronized. Note that we are looking here at chemical reactions (leading to the bursts) that are induced by a signal that works across glass barriers. Even though the study does not reveal the function of synchronous light bursts, it shows the capability of a supra-cellular organisation based on an endogenous source most probably of electromagnetic nature."
Some aquatic species were found that must interchange biophotonic signals , for example in :
" was found that autotrophic unicellular organisms (Euglena viridis), separated by cuvettes, affected the proliferation rate of heterotrophic unicellular organisms (Paramecium caudatum). Further, the heterotrophic unicellular organism affected also the proliferation rate of a multicellular heterotrophic organism (Rotatoria sp.) and vice versa. In the case when populations (of Euglena viridis and Paramecium caudatum) were shielded against electromagnetic fields in the optical spectrum from each other, no effects were measured."
Another kind of experiments in regard to communication possibilities are those that measure and do a statistical study of biophoton emissions, for example in  is measured the biophoton emissions between fish eggs and they found that:
" .. the main bulk of radiation is produced in form of short-time quasi-periodic bursts. The analysis of radiation temporal structure indicates that the information about egg age and growth is encoded via the values of time intervals between neighbor bursts with the height higher than some fixed level"
Also is proposed that internally in multicellular organism, independently of the external emissions through extracellular medium (where almost filled with water possibly has relatively low attenuating effect due to special characteristic of water in its relation to electromagnetic fields, see sections ) also are used nanotubes that serving as optical fibers connecting cells as proposed in , similar ideas are proposed for collagen structures the of extracellular matrix (that can both conduct and modify photon pulses coming from biological sources) and the more recently discovered primo.vessels .
" The primo-vessel contains lower absorption and scattering coefficients. It appears more transparent than its surrounding dermis and muscle , suggesting that it can transport light with high efficiency and act as an optical channel ."
Other approach that is explored in this section is the possible use of biophoton detection as a diagnostic tool in medicine.
Related to this is that of biophotonic emissions from cancer cells are discernible of those emitted by normal cells as is showed in  where is used the spectral power density variable as a detection method, which reveals differential distributions of the amplitude modulation of the flux density of the photon emissions, in  is showed that Only 1% “contamination” of a normal cell line by a malignant cell generated marked increase in photon emissions from the aggregate of cells.
There is a growing number of investigations that related biophoton emissions characteristics with the health status of the tested subject, for example in  biophoton emissions are used to distinguish cold patients from healthy subjects and they found a significant difference in the maximum spectral peak and photon emission ratio between the filter of 550nm and 495nm, which can be used in distinguish cold patients from healthy people.
Classical Chinese Medicine specifically have concepts that now are measurable thanks to different comparisons of the biophoton emissions and it is thought that acupuncture meridians can serve as biophoton guiding channels (a dedicated section ).
It may be considered that not only detection but application of biophotonic signals is now being used in various novel therapeutic methods, majorly this method are named low level light therapy or light stimulation, and in their supporting scientific material biophotons are not habitually mentioned (except some exceptions) but they are exposures to very low light intensities that are in the spectrum of endogenously generated biophotons [sections 15,16]
In , employing Cosic’s resonance recognition model for molecules (which proposes electromagnetic energy and information transfer between interacting biomolecules) was demonstrated that specific photon wavelengths within the visible range from mouse melanoma cells were associated with specific molecular pathways. The resonant recognition model can resolve some biological questions and may be related to the detected biophotons. (see section ).
It's interesting to note that from the research made we know that body parts shaped and highly structured (and/or mineralized) emitted more than the relatively unstructured, flat body parts. 
To finish mention that there is a big field of research on biophotons with an agricultural production motivation, especially emissions from seeds are often measured, for example see [19,20,21]. A curious phenomena are those discovered by Galileo at al [22,23] that biophotons emissions of seeds are synchronized to gravimetric tyde even if different species show different rates of germination and development, the synchrony between the biophoton emissions and gravimetric oscillations are still displayed in the different species when each of them is germinated and grown simultaneously irrespective of whether the seedlings are raised at a common location or at widely separated locations.
Of course, is not the only kind of investigation related to vegetal world, in [24,25] are photographed "plant auras" like phenomena that in fact are biophoton fields surrounding leafs.
3. Bókkon, I., et al. "Estimation of the number of biophotons involved in the visual perception of a single-object image: Biophoton intensity can be considerably higher inside cells than outside." Journal of Photochemistry and Photobiology B: Biology 100.3 (2010): 160-166.
17. Dotta, Blake T., et al. "Shifting wavelengths of ultraweak photon emissions from dying melanoma cells: their chemical enhancement and blocking are predicted by Cosic’s theory of resonant recognition model for macromolecules." Naturwissenschaften 101.2 (2014): 87-94.
20. Bertogna, Eduardo, Evandro Conforti, and Cristiano M. Gallep. "Simultaneous biophoton measurement of control and fluoride stressed seedlings samples." Microwave & Optoelectronics Conference (IMOC), 2013 SBMO/IEEE MTT-S International. IEEE, 2013.
22. Gallep, Cristiano M., et al. "Simultaneous and intercontinental tests show synchronism between the local gravimetric tide and the ultra-weak photon emission in seedlings of different plant species." Protoplasma (2016): 1-11.
25. Creath, Katherine, and Gary E. Schwartz. "Imaging" Auras" Around and Between Plants: A New Application of Biophoton Imaging." Journal of Alternative & Complementary Medicine: Research on Paradigm, Practice, and Policy 11.6 (2005): 951-953.
Very related sections:
↑ text updated: 13/08/2016
↓ tables updated: 13/01/2018