SPORE GERMINATION 



47 



Spore germination. De Bary (1864), it has previously been 

 stated, first noted that on germination swarm cells, rather than 

 germ tubes, emerge from the spore membranes. Jahn (1905) ob- 



FiG. 10. Types of spore germination and initiation of plasmodia among 

 slime molds. (Adapted from Gilbert.) A to F. Ceratiomyxa fructiculosa. 

 Aj uninucleate spore; B, the same spore, which has become four-nucleate; 

 C and D, segmentation into four bodies; E and F, fusion of cells to form 

 Plasmodium. G to M. Physanmi polycephalnm. G, uninucleate spore; 

 H and /, the wall has ruptured, the nucleus has divided, and the swarm 

 cells have begun to emerge; / and K, motile swarm cells; L, fusion of 



swarm cells; M, plasmodium. 



served that the membrane may be cracked open in some species, 

 whereas in others a circular, jagged pore is formed. In either 

 case, he believed, rupture resulted from increased osmotic pres- 

 sure. The change of stored glycogen within the spore into os- 

 motically active sugar resulted in increased osmotic pressure. 



