围氏马尾藻(Sargassum wightii)是广西涠洲岛、广东徐闻等海域的习见物种，为大型经济海藻。了解大型藻类的周年生长情况及其早期发育过程，可以推测藻体成熟时间并为其人工育苗和栽培等提供科学依据。本文报道了广东徐闻海域生活的围氏马尾藻的周年生长特点、温度对其排卵的影响及其有性生殖的早期发育过程，结果显示：围氏马尾藻周年生长情况可分为快速生长期、成熟期、衰退期和休止期4个时期，藻体平均长度在4月初达到最长(188.32 ± 43.77cm)，在4月和5月平均长度均超过180cm，而在7月下旬至11月上旬不超过5cm；围氏马尾藻为雌雄同托，卵细胞发育属8核1卵型；培养温度对其排卵过程至关重要，生殖托在15、27、30℃培养下无法排卵，在18~24℃培养下均可排卵，24℃培养下排卵时间最短，仅需3d便可排卵；受精卵在24℃下培养24h左右发育形成有假根的幼孢子体，幼苗培养30d便发育出第四片叶片。本研究结果为围氏马尾藻的生物学、生态学、人工育苗和栽培提供了基础资料。

Sargassum wightii is a common species in Weizhou Island of Guangxi, Xuwen of Guangdong and other sea areas, and is an economic macroalgae. Understanding the annual growth and early development of macroalgae can predict the mature time of thalli and provide scientific basis for artificial seedling and cultivation of macroalgae. This paper reports the annual growth characteristics, the effect of temperature on ovulation and the early developmental process of sexual reproduction of S.wightii living in the sea area of Xuwen, Guangdong. The results showed that the annual growth of S.wightii can be divided into 4 periods: fast growing period, mature period, decline period and resting period. The average length of thalli reached its miximum (188.32 ± 43.77cm) in early April, exceeding 180 cm in both April and May, and less than 5cm in late July to early November. The male and female reproductive parts of S.wightii are in the same receptacle, and the egg cell development belongs to 8-nucleui type. The culture temperature is very important to the ovulation process. Ovulation could not be achieved at 15, 27 and 30℃, but could be achieved at 18~24℃. The ovulation time was shortest at 24℃, only 3d. The zygotes developed into germlings with rhizoid buds at 24℃ for about 24h, and the seedlings developed a fourth leaflet after 30d of culture. The results of this study provide basic information for the biology, ecology, artificial seedling and cultivation of S.wightii.