174 THE VICTORIAN NATURALIST. [Vol. XXlII. 



I . 



NOTE ON THE PHOSPHORESCENCE OF AGARIC US 



(PLEUROTUS) GANDESCENS, Mull. 



By Alfred J. Ewart, D.Sc, Ph.D., F.L.S. 



[Read 'before the Field Naturalists' Olub of Victoria, lOth Dec, 190G.) 

 According to recent research* the phosphorescence of at least 

 one animal (Pholas dactylus) is due to the production of two 

 substances, luciferin and luciferase, which, when brought together, 

 produce an emission of light, probably as a result of chemical 

 action. In this case phosphorescence is possible outside of the 

 body or of the living cells. Opportunity was taken of the receipt 

 of some unusually fine luminous sporophores of Pleurotus 

 candescens to test the applicability of the above statement to a 

 luminous plant, but with entirely negative results. Only the gills 

 were luminous, and the luminosity was greatest between 20 and 

 30° C, becoming dim and fading at from 5 to 0° C. A slowly 

 fading luminosity was still present at 40-50° C., but it was immedi- 

 ately lost when the specimens were dropped in thin pieces into 

 boiling water. Large entire sporophores emitted rapidly fading 

 light for a second or two after being dropped in the boiling water. 



Entire specimens immersed in cold water (18° C.-20° C.) became 

 very faintly luminous in half to one hour, and the luminosity 

 immediately brightened on exposure to air. After being kept 

 under water for 4 hours the sporophores became non-luminous, 

 but began to glow within 5 to 10 seconds after re-exposure to air, 

 the luminosity being, however, patchy in distribution and absent 

 from all dead parts. 



No luminous Juice could be extracted from the sporophores, 

 although pressed portions of the gills may remain faintly luminous 

 until all the cells are dead. If strongly crushed the luminosity 

 disappears immediately. When sporophores are dropped into 

 spirit the luminosity rapidly fades and disappears, no recovery 

 being then possible. Dropped into carbon dioxide the luminosity 

 fades and disappears with equal, or even greater, rapidity, but in an 

 atmosphere of nitrogen the luminosity lasts for a somewhat longer 

 time, though fading from the commencement of the experiments. 



In this plant, therefore, the production of light is intimately 

 associated with the respiratory katabolism involved in the forma- 

 tion of spores, and any factor which diminishes the respiratory 

 activity also diminishes the production of light, these two 

 functions tracing closely parallel curves. As to the biological 

 significance of the luminosity, its restriction to the gills 

 shows that its present function is evidently to attract molluscs, 

 as well as creeping and flying insects, which may aid in the 

 distribution of the spores, but says nothing as to the primitive 

 origin of this special peculiarity, or as to why it should be 

 restricted to particular members of this genus. 



* Dubois, Compt. rend., 1896, T., cxxiii. , p. 653. 



