32 RESEARCHES ON FUNGI 



Premature Discharge of the Sporangia.— In the evening 

 Lepeschkin i placed a tuft of fruit-body primordia on a 2 per cent, 

 solution of sodium chloride. Next morning it was found that some 

 of the fruit-bodies had not developed sporangia and that others 

 had developed to maturity in the usual way. Plasmolytic experi- 

 ments showed that, whereas in the previous evening plasmolysis 

 of the fruit-bodies began with a 1-4 per cent, sodium-chloride 

 solution, in the morning it began with a 3-5 per cent, solution. 

 Thus the osmotic pressure had increased two and one-half times 

 during the night. Lepeschkin, in the morning, removed the fruit- 

 bodies from contact with the 2 per cent, salt solution and set them 

 on water. Two phenomena were then noticed : (1) the imperfectly 

 developed fruit-bodies greatly increased their excretion of water ; 

 and (2) the perfectly developed fruit-bodies, which had ceased or 

 were ceasing to excrete water, did not increase their excretion of 

 water but, instead, within 1-5 minutes exploded and shot away 

 their sporangia with a bang.^ These phenomena were doubtless 

 due to the increase of the turgor pressure in the sporangiophore 

 brought about by the transference of the fruit-bodies from the 

 2 per cent, salt solution to water. 



Lepeschkin also observed that, when mature fruit-bodies of 

 Pilobolus are subjected to chloroform or ether vapour by the 

 gradual method beginning with very small amounts, the discharge 

 of the sporangia is prematurely hastened. Thus by the gradual 

 method he subjected 70 fruit-bodies to chloroform or ether and 

 in other vessels kept 95 fruit-bodies in ordinary moist air. The 

 experiment began at 9 a.m. Of the 70 fruit-bodies treated with 

 narcotics, 20 had shot away their sporangia by 9.30 a.m., 65 by 

 10 A.M., and all by 11.30 A.M., whereas of the 95 untreated sporangia 

 not one had shot away its sporangium by 11.30 a.m. Lepeschkin 

 explained the earliness of discharge of the sporangia under the 

 influence of chloroform and ether by supposing that these narcotics 

 diminish the permeability of the plasma-membrane of the sporangio- 

 phore and so increase the turgor of the sporangiophore to the degree 

 required for the discharge of the sporangium before the usual time. 

 There are two forces to be taken into account in the discharge 

 1 W. W. Lepeschkin, loc. cit., p. 429. ^ Ibid., pp. 432-433. 



