Togashi Tatsuya, Cox Paul Alan
Marine Biosystems Research Center, Chiba University, Kamogawa 299-5502, Japan.
J Integr Plant Biol. 2008 Jun;50(6):648-52. doi: 10.1111/j.1744-7909.2008.00665.x.
By finding some important culture conditions as below, we succeeded in experimentally controlling the whole life history of a dioecious marine green alga, Bryopsis plumosa (Hudson) C. Agardh. In this study, we focused on the primary and secondary sex ratios (i.e. at inception and maturity) using these culture techniques. Gametogenesis was induced by culturing haploid gametophytes with Provasoli's enriched seawater (PES) medium under a 14:10 h light:dark cycle at 14 degrees C. Formed zygotes grew into diploid sporophytes, which were cultured for 3 months with PES medium under a 14:10 h light:nbsp;dark cycle at 18 degrees C. Then they were transferred into Schreiber medium and cultured under a 10:14 h light:dark cycle at 22 degrees C. Within 1 week, zoosporogenesis was observed. Zoospores were released within a couple of days. Each zoospore soon germinated and grew into a unisexual gametophyte. The primary sex ratio was examined in gametophytes that originated from a single sporophyte. The secondary sex ratio was studied in the field. Both were estimated as 1:1. Synchronized meiotic cell divisions might occur during zoosporogenesis dividing each sex-determining factor evenly among zoospores. Given the equal sex ratio at maturity, there seems to be no environmental factor that differentially affects the survival of male or female gametophytes in nature.
通过找出如下一些重要的培养条件，我们成功地通过实验控制了雌雄异株海洋绿藻羽藻（Bryopsis plumosa (Hudson) C. Agardh）的整个生活史。在本研究中，我们利用这些培养技术着重研究了初次和二次性别比（即在起始阶段和成熟阶段）。通过在14℃、14:10小时光照:黑暗周期条件下，用普罗瓦索利富海水（PES）培养基培养单倍体配子体来诱导配子发生。形成的合子发育成二倍体孢子体，将其在18℃、14:10小时光照:黑暗周期条件下用PES培养基培养3个月。然后将它们转移到施赖伯培养基中，在22℃、10:14小时光照:黑暗周期条件下培养。在1周内，观察到游动孢子形成。游动孢子在几天内释放。每个游动孢子很快萌发并发育成单性配子体。在源自单个孢子体的配子体中检测初次性别比。在野外研究二次性别比。两者估计均为1:1。在游动孢子形成过程中可能会发生同步减数分裂细胞分裂，将每个性别决定因子在游动孢子之间均匀分配。鉴于成熟时性别比相等，似乎不存在在自然环境中对雄配子体或雌配子体的存活有不同影响的环境因素。
