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MycorJiiza . 
SOME RECENT OBSERVATIONS ON MYCORHIZA. 
OME interesting additions to our knowledge of that striking, 
and, as is now known (see New Phytologist, Vol. I., p. 83, 
April, 1902), extraordinarily wide-spread phenomenon, “ Mycorhiza,” 
have recently been made by the Japanese observer Shibata. 
His work was chiefly done on infected roots of species of 
Podocarpus , on Psilotum triquetrum, and also on Alnns and Myrica. 
Podocarpus is of special interest in this connexion, since, according 
to the experiments of Nobbe and Hiltner, infected plants of this 
genus are able to assimilate free nitrogen. The cells of the root- 
tubercles (produced by the modification of secondary roots) soon 
become filled with masses of strongly-developed mycelium in which 
cross-walls are absent. The contents of the cells of the host early 
begin to react very markedly to the presence of the fungal hyphae ; 
not only does the cytoplasm become increased in amount, but the 
nucleus also grows in size and has more stainable contents, while at 
the same time it becomes irregular in form. It then elongates and 
divides into two by simple direct division, a process which continues 
till as many as eight nuclei are found in a single cell. They are 
irregular and lobed in shape, and appear as compact masses of 
chromatin. While these changes are taking place in the nuclei the 
fungus mycelium begins to shew signs of disorganisation; the 
contents of the hyphae become gradually lost, the thin walls at 
first collapse, and later, in spite of the fact that they consist largely 
of chitin, almost completely dissolved, so that finally scarcely a 
trace of the attacking fungus is to be found in the cells of the host. 
The behaviour of the nuclei and the progressive disorganisation 
of the fungal hyphae strongly suggest that a ferment or ferments 
have been secreted by the host-cells, and that this has led to the 
almost complete solution of the mycelium. Shibata has in fact 
actually demonstrated the existence of a proteolytic ferment in the 
infected tubercles of Podocarpus, since an extract of these when 
slightly acidified was found to dissolve fibrin, while an extract of 
similar uninfected tubercles had no such effect. It was further 
observed that the nuclei of the host-cells, after abosrption of the 
fungus, returned to their normal state, and were capable of dividing 
by the normal karyokinetic method, exhibiting the typical number 
of chromosomes. 
Similar cytological observations were made on the cells of the 
