Laminarialean plants undergo heteromorphic alternation of generations between the macroscopic diploid sporophyte and the microscopic haploid gametophyte. The generations change through the formation and release of asexual or sexual reproductive cells. It is difficult to monitor the release and diffusion of zoospores into the environment. Furthermore, even if zoospores can be detected, species identification remains difficult. This study attempted to develop a sensitive and fast identification method for laminarialean zoospores using quantitative PCR. In addition, we aimed to estimate the density of zoospores in natural seawater. Specific primers for Saccharina japonica and Undaria pinnatifida were designed and used to estimate the quantity of zoospores in seawater. DNA samples (environmental DNA) were collected from seawater once or twice each month for 2 years at the same area, and seasonal variations in the release of zoospores was monitored. The estimated maturation period based on the number of released zoospores in this study was comparable with those of the previously reported maturation periods of S. japonica and U. pinnatifida sporophytes. This supports the validity of our method in estimating zoospore release from laminarialean plants. The method will be a useful tool for ecological studies on these commercially relevant species.

中文翻译：

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通过实时 PCR 定量海水中的海带游动孢子

海带植物在宏观二倍体孢子体和微观单倍体配子体之间经历世代的异形交替。世代通过无性或有性生殖细胞的形成和释放而改变。很难监测游动孢子向环境中的释放和扩散。此外，即使可以检测到游动孢子，物种鉴定仍然很困难。本研究尝试使用定量 PCR 开发一种灵敏、快速的海带游动孢子鉴定方法。此外，我们旨在估计天然海水中游动孢子的密度。设计了 Saccharina japonica 和 Undaria pinnatifida 的特异性引物，并用于估计海水中游动孢子的数量。DNA 样本（环境 DNA）在同一地区每月一次或两次从海水中收集，持续 2 年，并监测游动孢子释放的季节性变化。根据本研究中释放的游动孢子数量估计的成熟期与先前报道的 S. japonica 和 U. pinnatifida 孢子体的成熟期相当。这支持了我们的方法在估计海带植物游动孢子释放方面的有效性。该方法将成为对这些商业相关物种进行生态研究的有用工具。japonica 和 U. pinnatifida 孢子体。这支持了我们的方法在估计海带植物游动孢子释放方面的有效性。该方法将成为对这些商业相关物种进行生态研究的有用工具。japonica 和 U. pinnatifida 孢子体。这支持我们的方法在估计从海带植物中释放游动孢子的有效性。该方法将成为对这些商业相关物种进行生态研究的有用工具。