Fungi, Ascomycetes, Ustilaginales, Uredinales . fertile layer isdifferentiated. In PucciniaPoarittn nuclear migrationssometimes take place be-tween the vegetative cellsat the base of the veryyoung aecidium. Thesecells may grow up, eitherat once or after division, toform fertile cells. The aecidiospores, then,are the products of asexualprocess by means of whichtwo nuclei become associated within thelimits of a single protoplasmic mass, form-ing the dikaryon or synkaryon of nuclei thus brought together do notfuse, but undergo simultaneous division(fig. 174), so that a daughter nucleus,
Fungi, Ascomycetes, Ustilaginales, Uredinales . fertile layer isdifferentiated. In PucciniaPoarittn nuclear migrationssometimes take place be-tween the vegetative cellsat the base of the veryyoung aecidium. Thesecells may grow up, eitherat once or after division, toform fertile cells. The aecidiospores, then,are the products of asexualprocess by means of whichtwo nuclei become associated within thelimits of a single protoplasmic mass, form-ing the dikaryon or synkaryon of nuclei thus brought together do notfuse, but undergo simultaneous division(fig. 174), so that a daughter nucleus, fromeach passes into even- new cell. Conjugatedivision is continued when the aecidiosporegerminates and a mycelium of binucleatecells is produced. The sporophyte of therusts is thus normally inaugurated in thefertile cells of the aecidium. It is not unusual to find spores andvegetative cells which contain three ormore nuclei ; in these, as in the binucleatecells, and, indeed, in multinucleate cells ofmany different groups of plants, conjugate. Fig. 1;.,. Phragmidium violaceum Wint.; migration ofei nil nucleus into fertile cell of caeoma, x 950; alterBlackmail.
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Keywords: ., bookcentury1900, bookdecade1920, booksubjectfungi, bookyear1922
