The visualization of natural luminescence of living cotton hairs.

Super-weak luminescence of individual living cotton cells was investigated. This phenomenon was observed under an optical microscope using a replica-reprint technique in conjunction with living cotton cells. Gelatin solution was used for visualization of luminescence in a polymer film deposited on the cotton cells. No luminescence was generated in dead and very young plant cells (1 day after flowering) but maximal luminescence was detected from apical parts of cotton hairs in the early growth stage (4-6 days after flowering). Emitted luminescence had a cone-like form for different varieties of cotton plants. This indicates a focusing of radiation connected with morphological and structural features of the apical part of cotton cells at early stages of their evolution. The electromagnetic nature of cotton cell luminescence has been shown by experiments using photomultiplier (PEM) sensing of ultraviolet radiation. Insertion of a cotton seed-bud in darkness on a PEM window increased the dark current by 6-8%. Radiation flux from developing cotton hair is actually more intense, but through the PEM window only a small part of the radiation was detected.