半叶马尾藻中国变种(Sargassum hemiphyllum var. chinese)是广泛分布于南海沿岸的大型经济海藻。为探究其有性生殖特点和人工育苗的可行性，本文首先利用光学显微镜对半叶马尾藻中国变种藻体、雌雄生殖托和生殖细胞的形态特征、受精卵的早期发育过程进行了观察。结果显示：半叶马尾藻中国变种成熟藻体呈黄褐色，株高0.8~1米，雌雄异株，具由重复二叉组成的盘状固着器。雌性生殖托呈黄褐色、圆柱形，表面长有较多的棘突，直径为0.46±0.05mm，长度为2.50±0.67mm；雄性生殖托颜色较浅、呈棒状，直径为1.01±0.18mm，长度为9.21±2.36mm。雌性生殖托释放的卵细胞属8核1卵型，椭球形或卵圆形，直径76.32±10.11μm，排卵后附挂于雌性生殖托上等待受精；雄生殖托释放的精子呈梨形，长度为27.52±5.43μm，具有鞭毛。受精后大部分受精卵会从生殖托脱落，固着于附着基上并开始早期发育。受精卵于第6小时开始第一次横分裂，随后经过数次横纵分裂、于第24h发育成“地雷状”幼孢子体，28d后出现原生叶。然后，本文还对适宜半叶马尾藻中国变种幼孢子体萌发的附着基质及适宜生长温度进行了探索。结果发现，经过7d培养后半叶马尾藻中国变种受精卵在布帘上萌发出的幼孢子体数量为7.25±3.64个·cm^-2，长度为1.38±0.35mm，显著高于其他附着基；室内悬浮培养实验证明，25℃条件下幼孢子苗的存活率为90％，藻体生长速率为90.1μm·d^-1，显著高于其它温度条件。研究结果为半叶马尾藻中国变种的早期发育研究和规模化人工苗种繁育提供了数据支撑和理论依据，有助于推动自然海区马尾藻场的快速构建，助力中国近岸海洋生态系统快速修复。

Sargassum hemiphyllum var. chinese is a significant economic seaweed with wide distribution along the coast of the South China Sea. To investigate the sexual reproductive characteristics and the feasibility of artificial seedling propagation, this study employed optical microscopy to examine the morphological features of the thallus, male and female receptacles, and early developmental stages of fertilized eggs in the Sargassum hemiphyllum var. chinese. The results revealed that the mature thallus of the Chinese variant exhibited a yellow-brown hue, reaching a height of 0.8 to 1 meter. It displayed dioecious traits and possessed discoid holdfasts composed of repetitive bifurcations. The female receptacles appeared yellow-brown and cylindrical, adorned with numerous surface spines, measuring 0.46±0.05 mm in diameter and 2.50±0.67 mm in length. Conversely, the male receptacles were lighter in color, adopting a rod-like morphology, with a diameter of 1.01±0.18 mm and a length of 9.21±2.36 mm. Eggs released from the female structures exhibited an 8-nucleate 1-egg configuration, either ellipsoidal or oval, with a diameter of 76.32±10.11 μm. Following ovulation, these eggs adhered to the female structures awaiting fertilization. Sperm released from the male structures were pear-shaped, measuring 27.52±5.43 μm in length and equipped with flagella. Post-fertilization, the majority of fertilized eggs detached from the receptacles, affixing to substrates and commencing early developmental processes. Within 6 hours, these fertilized eggs underwent their initial transverse division, subsequently progressing through multiple transverse and longitudinal divisions, ultimately culminating in the development of landmine-liked sporophytes within 24 hours, with primary leaves emerging after 28 days. Additionally, this study investigated suitable substrates for the germination of sporophytes and optimal growth temperatures for the Sargassum hemiphyllum var. chinese. Results indicated that after 7 days of cultivation, the mesh curtain yielded a significantly higher germination rate of 7.25±3.64 sporophytes per cm2, measuring 1.38±0.35 mm in length compared to other substrates. Indoor suspension culture experiments further revealed a 90% survival rate of sporophytes at 25°C, with a thallus growth rate of 90.1μm·d^-1, significantly outperforming other temperature conditions. These findings furnish valuable data support and theoretical foundations for the early developmental study and large-scale artificial seedling propagation of theSargassum hemiphyllum var. chinese, thereby facilitating the rapid establishment of natural Sargassum habitats in coastal regions and contributing to the swift rehabilitation of China's nearshore marine ecosystems.