宽礁膜的生活史

在国内首次观察描述了宽礁膜(Monostroma latissimum Wittrock)生活史各阶段的形态结构特征和发育变化,并对其单性生殖进行了周年培养和观察。大型的雌雄异体的膜状配子体成熟后,放散双鞭毛的配子,小型的球状孢子体成熟后放散四鞭毛的游孢子,其生活史是单倍体的配子体与二倍体的孢子体互相交替的异形世代交替。另外,在生活史中还发现合子和孢子囊的二分裂增殖方式,一年生配子体和二年生孢子囊等现象。未接合的雌、雄配子固着后变成球状单细胞体,室内培养后发育成成熟的单性孢子囊,并放散四鞭毛的游孢子,这些游孢子固着后,可直接发育成膜状的配子体,单性生殖也可以用来进行人工育苗。

Life History of Monostroma latissimum

In the present study the authors observed and reported the morphological characters anddevelopment process in all stages of the life history of Monostroma latissimum Wittrock for the first timein China. The process of parthenogenesis has also been observed in yearly culture. When the dioeciousmacrogametophytes mature, they liberate biflagellate gametes, and when the spherical microsporophytesmature, they produce quadriflagellate zoospores. Its life history is a periodical heteromorphic alternation ofhaploid gametophyte generation and diploid sporophyte generation. In addition, this study indicates themultiplication of zygotes and cysts by binary fission, two-year-old cysts compared with gametophytes livingfor one year in the life history of M. latissimum. The male and female gametes that do not conjugate alsoundergo parthenogenesis as they adhere to the substrates. They become unicellular bodies, spherical inshape, somewhat smaller than the zygotes. Then, the cysts of parthenogenesis mature and liberate anumber of quadriflagellate swarm spores. These spores adhere to substrates and germinate directly intothe leaf fronds. As for zygotes, parthenogenesis of the male and female gametes also can be used forartificial seeding of M. latissimum in culture.