小麦条锈菌异核新菌系的筛选及核游离试验研究

ON THE SCREENING OF NEW HETEROCARYONS OF WHEAT STRIPE RUST AND ITS NUCLEAL DISSOCIATION

采用生物学和细胞学方法研究小麦条锈菌的异核作用。不同小种的单孢菌系间的混合接种繁殖筛选出三个新菌系。新菌系的毒性明显不同于相应的原始菌系,新菌系夏孢于芽管的多核率较原始菌系高,这表明三个新菌系是经异核作用产生的。异核体的多核率随继代接种而降低,但有的菌系的毒性仍保持稳定。在采自陇南自然条件的条锈菌的夏孢子群体中,存在有3核和4核体,感病品种上夏孢子的多核率明显高于抗病品种。这一结果表明小麦条锈菌异核作用在感病品种上的发生机率较在抗病品种上的为高。

The heterocaryosis of wheat stripe rust was studied with biological and cytological methods. Three new isolates had been obtained from the mixtures of different races, reproducing on the same wheat cultivar simultaneously. It was found that the virulence of the new isolates was obviously different from that of original races and the multinucleal rate in the new isolates was much higher than that in original races, which indicated that the new isolates were produced by means of heterocaryosis. The multinucleal rates of the nes isolates were demonstrated to decline with generations, but the virulence of two isolates of them kept stable. The urediospores with three or four nuclei were observed in field samples from south Gansu Province and the multinucleal rate in the urediospores from susceptible wheat cultivars was much higher than that from the resistant cultivars, which showed that the chance for heterocaryosis of wheat stripe rust on susceptible cultivars may be greater than that on the resistant cultivars.