We evaluated the life cycle of Leathesia marina through molecular analyses, culture studies, morphological observations, and ploidy measurements. Macroscopic sporophytes were collected from two localities in Atlantic Patagonia and were cultured under long‐day (LD) and short‐day (SD) conditions. Molecular identification of the microscopic and macroscopic phases was performed through the cox3 and rbcL genes and the phylogeny was assessed on the basis of single gene and concatenated datasets. Nuclear ploidy of each phase was estimated from the DNA contents of individual nuclei through epifluorescence microscopy and flow cytometry. Molecular results confirmed the identity of the Argentinian specimens as L. marina and revealed their conspecificity with L. marina from New Zealand, Germany, and Japan. The sporophytic macrothalli (2n) released mitospores from plurilocular sporangia, which developed into globular microthalli (2n), morphologically similar to the sporophytes but not in size, constituting a generation of small diploid thalli, with a mean fluorescent nuclei cross‐sectional area of 3.21 ± 0.7 μm². The unilocular sporangia released meiospores that developed two morphologically different types of microthalli: erect branched microthalli (n) with a nuclear area of 1.48 ± 0.07 µm² that reproduces asexually, and prostrate branched microthalli (n) with a nuclear area of 1.24 ± 0.10 µm² that reproduces sexually. The prostrate microthalli released gametes in LD conditions, which merged and produced macroscopic thalli with a nuclear cross‐sectional area of 3.45 ± 0.09 µm². Flow cytometry confirmed that the erect and prostrate microthalli were haploid and that the globular microthalli and macrothalli were diploid.

中文翻译：

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在体外培养下，Leathesia marina（Chordariaceae，Phaeophyceae）生命周期的隐性单倍体阶段

我们通过分子分析，培养研究，形态学观察和倍性测量评估了Leathesia marina的生命周期。从大西洋巴塔哥尼亚的两个地方收集宏观孢子体，并在长日（LD）和短日（SD）条件下进行培养。通过cox 3和rbc L基因对微观和宏观阶段进行分子鉴定，并根据单个基因和级联数据集评估系统发育。通过落射荧光显微镜和流式细胞术从单个核的DNA含量估算每个相的核倍性。分子结果证实了阿根廷标本的身份为L. marina并揭示了它们与来自新西兰，德国和日本的玛丽娜·L。玛丽娜的专一性。孢子体巨藻（2n）从小眼孢子囊释放出孢子，发展成球状微藻体（2n），形态上与孢子体相似，但大小不一，构成了一个小二倍体藻体的产生，平均荧光核截面积为3.21。 ±0.7微米²。单眼孢子囊释放出的中子孢子发育出两种形态不同的微藻类：无核繁殖的直立分支微藻（n）为1.48±0.07 µm ²，而无核孢子囊发育成分支微藻（n），其核面积为1.24±0.10 µm。²有性繁殖。strate状微thalli在LD条件下释放了配子，这些配子合并并产生了具有3.45±0.09 µm ²核横截面的宏观thalli 。流式细胞仪证实直立和strate缩微th是单倍体，球形微th和巨macro是二倍体。