SIGNIFICANCE OF CONJUGATE NUCLEI 277 



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Fig. 145. — Coj:)rinus lagoj^us. Diagram to illustrate the mutual diploidisation of 

 two haploid mycelia of opposite sex. It has been assumed tliat all the cells of 

 both of the hyphae shown become diploidised, that nuclei may pass through a 

 hyphal fusion in both directions, and that the septa break down in turn as 

 required for the passage of nuclei from one cell to another. Xo. 1 : a hypha 

 / gr of a haploid myceliuna (AB) is growing toward, and soon will meet and 

 fuse with, the cell d of the hypha c c? e of a haploid mycelium (ab). No. 2 : 

 fusion has taken place, and the (AB) nucleus of / is dividing. No. 3 : one of 

 the daughter (AB) nuclei has passed into the cell d, thus diploidising it. 

 No. 4 : a wall now separates the cells d and /, and the (AB) nucleus in the 

 cell d is dividing. No. 5 : the wall between the cells c and d is partly broken 

 down, and one of the daughter (AB) nuclei has passed through it from d to c. 

 No. 6 : the (AB) nucleus of the cell d has again divided and has sent one of 

 its daughter (AB) nuclei into the cell e. Thus the haploid cell/ has diploidised 

 the haploid cell d, and the diploid cell d in its turn has diploidised first 

 the haploid cell c and then the haploid cell e. Nos. 7, 8, and 9 show the 

 diploidisation of the cells/ and g of the (AB) hypha by means of nuclei derived 

 from the formerly haploid mycelium (ab). No. 7 : the (ab) nucleus cf the 

 conjugate pair of nuclei (AB) and (ab) in the cell d is now dividing. No. 8 : the 

 wall between the cells d and / is partly broken down, and one of the daughter 

 (ab) nuclei has passed through it from d to /. No. 9 : the (ab) nucleus of the 

 cell / has divided and has sent one of its daughter (ab) nuclei into the cell g. 

 Thus the diploidisation of all the cells shown in the two hyphae has been 

 accomplished. The further development of a diploidised hypha including the 

 conjugate division of the conjugate pairs of nuclei and the formation of clamp- 

 connexions is represented diagrammatically in Fig. l4Ct. Higlily magnified. 



