Dear Nadav Vulkan some papers have been published on this regard. As for other radiation sources, it's highly convinient after treatment change the cultures to fresh medium.

I don't think so. UV usually do not enter inside and only sterilize the surface

Plants are highly sensitive to mainly UV-B radiation. UV-B radiation damages cell membranes and all organelles within the cell, including the chloroplasts, mitochondria, and deoxyribonucleic acid (DNA) within the nucleus so there are definitely chances of UV B affect plant harmones.

Thank you all very much.

@Ricardo Julian Licea-Moreno, do you have any recommendation for such papers?

Stoien, J. D., & Wang, R. J. (1974). Effect of near-ultraviolet and visible light on mammalian cells in culture II. Formation of toxic photoproducts in tissue culture medium by blacklight. Proceedings of the National Academy of Sciences, 71(10), 3961-3965.

Merwald, H., Klosner, G., Kokesch, C., Der-Petrossian, M., Hönigsmann, H., & Trautinger, F. (2005). UVA-induced oxidative damage and cytotoxicity depend on the mode of exposure. Journal of Photochemistry and Photobiology B: Biology, 79(3), 197-207.

Thank you Ricardo.

Documented evidences reveal that concentration of Auxins PGR is reduced by UV-B irradiation.

I would like to recommend these articles for getting more information:

1. Mannucci, A., Mariotti, L., Castagna, A., Santin, M., Trivellini, A., Reyes, T. H., ... & Quartacci, M. F. (2020). Hormone profile changes occur in roots and leaves of Micro-Tom tomato plants when exposing the aerial part to low doses of UV-B radiation. Plant Physiology and Biochemistry, 148, 291-301.‏

2. Yang, H., Zhao, Z., Qiang, W., An, L., Xu, S., & Wang, X. (2004). Effects of enhanced UV-B radiation on the hormonal content of vegetative and reproductive tissues of two tomato cultivars and their relationships with reproductive characteristics. Plant growth regulation, 43(3), 251-258.‏

Ricardo Julian Licea-Moreno, Dear, it is very much usual practice of the tissue culture industry that the culture vessels containing medium used to exposed to UV light under the LAF or out of LAF before subculture and no adverse effects are observed in the plant growth and development. But there may be chance of changes in the molecular structure of the PGRs if exposed to longer duration.

Nadav Vulkan

Dear Nadav Vulkan

I don't think that irradiation of plates containing media would change the PGRs efficacy or concentration. Generally this practice is followed to kill organisms on surface of vessels which may cause contamination during inoculation.