金针菇生活史各阶段核相研究

Behavior of nuclei in life cycle of Flammulina velutipes

对金针菇Flammulina velutipes生活史各阶段的菌丝体、子实体、担孢子等进行荧光显微观察。结果表明,金针菇单个担孢子发育而来的同核体菌丝为单核,无锁状联合,部分单孢菌株能形成同核子实体,同核子实体的原担子中只有1个核,该核在担子中进行一次有丝分裂形成纵向排列的2个子核,担子发育停止,同核子实体不产生担孢子;具有可亲和交配型的两个同核体菌丝经过质配形成异核体菌丝,异核体菌丝双核,具有锁状联合,能形成异核子实体,异核子实体的原担子中具有2个核,这2个核经过核配融合为1个二倍核,二倍核在担子中进行减数分裂形成4个单倍子核,4个子核分别进入4个担孢子中,随着担孢子继续发育,其中的单核再进行一次有丝分裂,成熟担孢子为双核,但这2个核是同质的。单核菌丝和双核菌丝都能产生粉孢子,且产生的粉孢子均为单核。

Different stages of life cycle of Flammulina velutipes were observed using fluorescence microscopy. Mycelia formed from a single germinating basidiospore was monokaryotic and had no clamp connections. Parts of single-basidiospore isolates could form homokaryotic haplont fruiting bodies. Probasidia of homokaryotic fruiting bodies in the beginning contained one haploid nucleus that underwent once mitosis producing two incompatible nuclei and the development of the basidium became stagnant. Thus, the homokaryotic fruiting bodies were sterile. A pair of monokaryotic myceiia with compatible mating types formed heterokaryotic mycelium via plasmogamy. Heterokaryotic mycelia with two nuclei could produce clamp connections, and formed heterokaryotic fruiting bodies. Probasidia of heterokaryotic fruiting bodies had two compatible haploid nuclei which fused and formed a diploid nucleus subsequently. The diploid nucleus underwent meiosis and produced four haploid nuclei and each of them migrated into four basidiospores respectively through sterigmata. Each basidiosporic nucleus underwent mitosis producing two haploid nuclei. Thus, mature basidiospores of the heterokaryon were dikaryotic but homogeneous. Both homokaryotic mycelia and heterokaryotic mycelia can produce uninuclear iodia.