Phj'siologie. 587 



Knight, R, C. and J. H. Priestley. The Respiration of Plants 

 under Various Electrical Conditions. (Ann. Bot. XXVIII. 

 p. 135—161. 6 ligs. 1914.) 



In field experiments carried on for several years, plants, other- 

 wise under normal conditions, have been subjected to an electrical 

 discharge from an overhead S3'stem of wires during a large part of 

 their growing period, acceleration of growth and increase in yield 

 having been constantly reported. This treatment must considerably 

 alter many factors in the plant habitat and in the plant's reaction 

 to this habitat, hence it is difficult to ascribe the effect apparently 

 due to the electric discharge, to any particular physiological cause. 

 The present paper gives some of the first results of an attempt to 

 analyse the effect of the discharge on the plant bj' laboratory 

 investigation of the effect produced by such discharge on one phy- 

 siological function, respiration being the function first selected be- 

 cause this as measured by the Output of carbon dioxide can be 

 determined fairly accuratel)^ but especially because the amount of 

 carbon dioxide evolved might give a good indication of the progress 

 of katabolic processes in the plant. The experiments made b}' the 

 aulhors have shown that while a distinct increase in carbon Output 

 occurs during electrification, this increase can be wholly attributed 

 to a rise of temperature taking place owing to the production of 

 heat during the discharge, hence they conclude that the explanation 

 of the acceleration phenomena is not to be found in the response 

 of the respiratory function of the plant to electrification. 



F. Cavers. 



Lebard, P., Remarques sur l'ouverture ä la germin ation 

 de quelques akenes de Liguli flores. (Rev. gen. Bot. XXV. 

 p. 396-413, 432-442. 15 fig. 1 pl. 1913.) 



L'akene des Liguliflores se compose de deux parties, l'akene 

 proprement dit contenant la graine et le podocarpe, tres court 

 sauf dans Podospennum, qui a la valeur d'un pedonente floral; ä 

 la maturite, le parenchyme cortical du podocarpe se resorbe par- 

 tiellement, la partie axiale constituant l'entonnoir; dans sa partie 

 superieure. Tenlonnoir presente, par resorption du parenchyme 

 central, une cavite qui prolonge celle de l'akene proprement dit. 

 La structure de l'akene varie suivant les especes et aussi, pour une 

 espece donnee, suivant le niveau, considere; on y trouve toujours 

 des bandes fibreuses longitudinales separees, au moins ä la base, 

 par des regions parenchymateuses ou lacuneuses de moindre 

 resistance. 



La dehiscence est d'ordinaire passive; l'augmentation de volume 

 de la radicule provoque, ä la base du fruit, suivant les lignes de 

 faible resistance, l'apparition de fentes de dehiscence, mais d'ordi- 

 naire une de ces fentes se prolonge plus ou moins vers le sommet 

 par suite du retournement geotropique de la radicule et sous la 

 poussee des cotyledons. Le fruit de Podospermutn laciniatum etablit 

 le passage entre les fruits indehiscents et les fruits dehiscents: la 

 radicule provoque seulement la dehiscence de l'entonnoir, l'ouver- 

 ture du podocarpe etant due ä Taction de l'humidite sur les bandes 

 fibreuses diversement orientees qu'il contient. II y aurait enfin une 

 relation entre le mode de dehiscence et la forme des cotyledons, 



H. Chermezon. 



