蛹虫草(Cordyceps militaris)无性型的多型现象*

在萨氏琼脂和PDA上,蛹虫草Cordycepsmilitaris（Vuill）Fr.无性型,蛹草拟青霉Paecilomycesmilitaris(Kob）Br.＆Sm．的一些单孢子株可自发产生突变,基于多型现象及其它形态特征可分三种类型：（1）具野生型菌株特征;产孢结构拟青霉型（Paecilomyces－type）,稳定,菌落通常不自发产生角变,大多数单孢子株属此类群。（2）属此类群的单孢子株,在PDA上可形成亮褐色至橙黄色的角变,它们典型的产孢结构为瓶梗轮生,分生孢子常聚集成头状的轮枝孢型（Verticillium－type）。在查氏培养基上则相反,拟青霉型的产孢结构占优势。单孢子株Cm-71是这一类群的代表。（3）单孢子株Cm－42是在所观察单孢子株中形态特征独特的菌株。在PDA上菌丝生长纤细,蛛网状,产孢结构轮枝孢型。蛹草拟青霉对氯酸钾（KClO3）不敏感,在浓度为6％（W／V）的KMM培养基上,23～24℃14天菌落的直径仅1～2cm,无气生菌丝生长。各单孢子株形成的不利用硝酸盐突变株（nit突变株）的途径和形态特征,也可分成类似于粉被虫草CordycepspruinosaPeteh不利用硝酸盐突变株（nit突变株）的三种类型。

THE PLEOMORPHISM IN THE ANAMORPH OF CORDYCEPS MILITARIS

Single spore strains of Paecilomyces militaris, anamorph of Cordycepsmilitaris, spontaneously produced mutahons on Sabouraud agar and PDA. Seventy--fourstrains were isolated from a wild-type strain Cm-1 of this fungus. Theirmorphological characters could be divided into three groups. Single spore strains inGroup I had wild--type features, including conidiogenous strUcture of thePaeciloml'ces--type, which were stable, without spontalleous sector on colonies. Most ofsingle spore strains were included in aams group. In Group 2, typical conidiogenousstructures of the genus Paecilomyces could be observed and light brown to orangeyellow sectors readily formed from colonies on Sabouraud agar and PDA. Somesectors always appeared to bear conidiogenous structures of Verticillium on PDA, inwhich conidiogenous cells (phialides) were in whorid and the conidia aggregated inheads. However, on Czapek ager these isolates always aPPeared to bear conidialchains like a species of Paecilomyces. The pleomorphisms that included bothPaecilomyce.rtutype and Verticillium-type conidigenous stmctUres even could beobserved on the same hypha or whorl. The single spore strain Cm--71 was typical inthis group. In Group 3, only strain Cm--42 was discovered so far. ItS characters weresubarachnoid hyphae, with conidiogenous strllctllres of Verticilliu~type often occurringon PDA. It was very similar to the sector of strain Cm--71. Staining with 20"g / mlHoechst 33258 showed that all of nuclei in GrouP 1 and the original strain in GrouP2 were normal (ca. 6 pairs of chromosomes), but the nuclei in conidia of strain Cm--2and a sector tyom strain Cm--71 were smaller and some nuclei sometimes were near tOthe wall of conidia. The anamorph of COrdyceps militaris was not very sensihve topotassium chlorate, an effechve concentyahon for mutation was up tO 6% but was notl.5--2% like as in most of the references Published. On KMM containing 6% (w / v)KCIO,, the diameter of colony was only l-- Zcm after incubahng at 23-- 24oC for 14days. Mycelia were thin and grew loosely, without growth of aerial hyphae. Colonieson KPS containing the same concentrahon of KCIO, as in KMM were white, flat anddensely velvet, l.5-- Zcm in diameter. Potenhal formation of nityate non--utilizingstrains (nit mutant) on KPS was different in a single spore strain. They could bedivided into three types.A rahonal genetics basis of pleomorphism of Paecilomyces militaris was discussedin this paper.