关于茭白黑粉菌的正名问题

ON THE NAME OF THE SMUT OF ANNUAL WILDRICE

茭白黑粉菌在文献中出现Yenia esculenta(P.Henn.)Liou及Ustilago esculenta P.Henn.两个名字。现经形态发生学的研究以明确新名字是否有效。此菌冬孢子没有休眠期,孢子成熟后在适宜的环境中即可萌发。萌发的最适pH值为6;最适温度为25％;不需要外界光的诱导,在黑暗条件下也能正常萌发;培养基中的营养成份对孢子萌发的速率有一定影响。冬孢子在不同的环境条件下,其萌发形态及方式都是稳定的:孢子萌发时产生有隔的担子或先菌丝(promycelium)。该先菌丝起初可以是无隔的,但生长到一定程度,便产生分隔,分隔多为2—4个。初生的先菌丝和小孢子是单核的,但成熟的先菌丝、小孢子及短菌丝细胞内均是双核的。可以认为,该菌的双核期在整个生活史中占有相当长的时间,它只有短暂的单核期。没有发现先菌丝、小孢子彼此之间或相互间融合的现象;未见到双核的融合及减数分裂过程。茭白黑粉菌在人工组合培养基上生成厚壁的孢子,较自然界中的冬孢子为大,但萌发方式则相同。最后作者等认为茭白黑粉菌仍应保留在Ustilago属中,而Yenia esculenta(P.Henn.)Liou的名字是无效的。

According to the morphogenesis studies of the Annual Wildrice Smut fungus,no resting period has been found in the teliospores. The germination occurs immediately after maturity under adequate conditions. The optium pH for germination is pH 6, and the optimum temperature is 25℃. The germination occurs readily in darkness, however it may be accelerated by light and effected by various nutrients in media. The mode of germination of teliospores is stable at different conditions. The teliospores germinate to produce a septate promycelium. However, the young promycelia are nonsepatate and become divided by 2—4 septa later. Therefore, the writers are of the opinion that this fungus should be attached to the genus Ustilago (Pcrs.) Rooussel instead of Yenia Liou.Under microscope and electro microscope, the young promycelia are sporidia are shown each containing one nucleus, but the matured promycelia and sporidia are binucleate. It is thus considered that the binucleate phase covers a quite long period in the whole life cycle. It has never been found that either promycelia or sporidia have a tendency to fuse together. No fusion of the two nuclei in binucleate cells as well as the process of meiosis are observed.Chlamydospores can be produced on synthetic media in which the colonies are brown in color with age. The mature spores produced on synthetic media are somewhat larger than those produced in the host-tissue, but the mode of germination of the former is similar to the later. The writers suggest that the name Yenia esculenta (P. Henn.) Liou is no more valid and Ustliago tsculenta P. Henn. should be used.