Chapter VII 



59 



The Chondriome 



In the Myxomycetes and Plasmodiophoraceae in which CoWDRY, 

 Lewitsky, and Milovidov have studied the chondriosomes in all 

 stages of development (spores, zoospores, myxamoebae, plasmodia), 

 these elements remain constantly in the state of mitochondria or 

 short rods and never become chondrioconts. During sporogenesis 

 they are distributed among the spores (Fig. 24). 



The development of the chondriome in one of the Blastocladia- 

 ceae, Allomyces arbusculus, is known from a recent study of WlNS- 

 Low Hatch. In the mycelium the chondriome is represented ex- 

 clusively by long slender chondrioconts which appear to thicken 

 at the extremities of the hyphae. At the time of gametogenesis, 

 walls at the extremities of the hyphae cut off two gametangia, the 

 female being terminal, the male subterminal, both enclosing nu- 

 merous chondrioconts which are 

 more abundant in the female 

 than in the male gametangium. 

 The chondriosomes are distrib- 

 uted about the various nuclei of 

 the two gametangia, forming 

 around each nucleus an en- 

 tangled network of chondrio- 

 conts. Then, at the close of 

 gametogenesis, the chondrio- 

 conts in each gamete undergo a 

 fragmentation by which they are 

 reduced to numerous, very small, 

 mitochondria. These subse- 

 quently grow, then fuse, forming 

 about each nucleus a sort of 

 reticulate mantle which seems to 

 be transformed later into a chro- 

 matic, homogeneous cap ap- 

 pressed to the nucleus on one 

 side (nuclear cap). Each gamete 

 when mature encloses, there- 

 fore, a nuclear cap seemingly of 

 mitochondrial origin, occupying 

 the regions of the cell opposite to the insertion pomt of the flagel- 

 lum. Hatch compares this cap to the limosphere of moss anthero- 

 zoids and to the "Nebenkern" of some animal spermatozoids (Dip- 

 tera). Nevertheless the mitochondrial origin of this nuclear cap 

 seems still to demand some verification (Fig. 25). 



The development of the chondriosomes is known particularly m 

 the Saprolegniaceae in which we have been able to follow different 

 species {Saprolegnia, Achlya, Leptomitus) with the greatest accu- 

 racy during their entire development, not includmg the sexual pro- 

 cess (Figs. 26, 27) . The chondriosomes of these fungi appear m the 

 extremities of growing hyphae as relatively large mitochondria. 

 Immediately behind the tip, these elements begin to elongate, first 

 becoming rods, then thin, undulating and often branched, chondrio- 





r 





■^' 



Fig. 23. — The chondriome in fungi. A, 

 developing basidium of Coprinus; B, young 

 basidia of Psalliota cainpeatris; C, young 

 sporangium of Rhizopus nigricans: D. conidio- 

 phore of Penicillium glaucum; E, tissue from 

 the foot of Psalliota campestris; F. yeast, 

 Sporoboloviyces roseus. 



