The subtidal kelp Nereocystis luetkeana (hereafter Nereocystis) maintains an upright stature by producing a single gas‐filled float (pneumatocyst) that provides buoyancy. The ability of Nereocystis pneumatocysts to inflate with gas underwater is peculiar, and the gas composition of pneumatocysts has been the topic of several studies over the last 100 years. Past studies of pneumatocyst gases only examined large sporophytes, leaving open questions about the origins of these gases and how gas composition may change during development. In this study, we use developmental time as a means to understand the origin and physiological mechanisms that give rise to different gases within Nereocystis pneumatocysts. Total gas composition was measured across a range of pneumatocyst sizes (5–725 mL). Contrary to previous studies that documented pneumatocyst gas concentrations to be similar to air, this study found internal gas levels of CO, CO₂, and O₂ to be 1.2 ± 0.8%, 0.6 ± 0.2%, and 59.9 ± 13.6%, respectively. Our data suggest that the composition of gases does not change as pneumatocysts grow and that the rate of each gas added is approximately proportional to changes in pneumatocyst volume. Therefore, cells constituting the pneumatocyst wall are likely producing more gas (per surface area) to fill pneumatocysts as they expand, maintaining proportional gas composition and corresponding internal pressure.

中文翻译：

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牛海带Nereocystis luetkeana（Phaeophyceae）发育中的肺囊肿的气体成分1。

潮下海带Nereocystis luetkeana（以下Nereocystis）通过产生一个单一的气体填充的浮子（pneumatocyst），其提供浮力保持直立身材。水下神经性囊肿的Nereocystis气肿具有奇特的膨胀能力，并且在过去100年中，肺气肿的气体成分一直是许多研究的主题。以往对肺囊肿气体的研究仅检查了大型孢子体，这仍未解决这些气体的来源以及气体成分在发育过程中如何变化的问题。在这项研究中，我们将发育时间作为一种手段来了解引起神经囊肿内不同气体的起源和生理机制。肺囊肿。测量了各种气肿大小（5-725 mL）的总气体成分。与先前的记录表明气肿气体浓度与空气相似的研究相反，该研究发现CO，CO ₂和O _2的内部气体水平分别为1.2±0.8％，0.6±0.2％和59.9±13.6％。我们的数据表明，随着肺囊肿的生长，气体的组成不会改变，并且每种气体的添加速率与肺囊肿体积的变化大致成比例。因此，构成肺气囊壁的细胞在膨胀时可能会产生更多的气体（每表面积）以填充肺气囊，从而保持比例的气体成分和相应的内部压力。