锥状施克里普藻孢囊的多种形态特征

休眠孢囊是某些甲藻生活史的重要阶段,它被认为是甲藻赤潮爆发的种源。通过观察我国沿海海域采集的锥状施克里普藻（Scrippsiella trochoidea（Stein）Loeblich）休眠孢囊的类型以及形态特征,并将实验条件下形成的休眠孢囊与海区沉积物中休眠孢囊的形态特征进行比较,结果表明,锥状施克里普藻细胞在20°C、12小时光照/12小时黑暗、f/2培养基和f/2-N培养基中分别培养至第14天和第8天,可以观察到休眠孢囊的产生。培养30天后,培养液中有大量休眠孢囊,将藻液避光保存90天后,观察到培养基中有4种类型的休眠孢囊产生：（1）球形到椭球形（长25-39μm）,钙质外壁,稀疏或密被钙质附属物（长1-4μm）;（2）球形（直径为29-35μm）,钙质外壁,附属物非钙质（长0.5-1.5μm）;（3）球形到椭球形（长29-35μm）,钙质,表面光滑,无附属物;（4）球形（直径24-35μm）,有机外壁,无附属物。第1种类型的孢囊最为常见,分别占到2种培养条件下所得全部孢囊的77.70%和95.18%。从沉积物中所得的孢囊多属于第1种类型。分析了实验条件下形成不同类型休眠孢囊的原因和比例,同时探讨了海区沉积物中形成多种孢囊形态特征的原因,为锥状施克里普藻孢囊的生态研究提供了依据。

Morphological Characters of Scrippsiella trochoidea Cysts

Resting cysts play an important role in the life cycle of some dinoflagellates and are considered to be one of the initiation factors of algal blooms. We described the types and morphological diversity characters of Scrippsiella trochoidea (Stein) Loeblich cysts from in situ sediment samples and in different culture conditions. S. trochoidea cells were maintained in f/2 or f/2-N at 20°C with a 12 h light/12 h dark cycle. After 14 or 8 days incubation, respectively, the resting cysts were observed in the two different media. After 30 days, the cultures were preserved in darkness, and 4 types of resting cysts were found after another 90 days: (1) spherical to ovoid cysts (25-39 μm long) covered by a sparse or numerous calcareous attachments (1-4 μm long) and a calcareous surface; (2) spherical cysts (29-35 μm diameter) with a noncalcareous surface attachment, calcareous surface; (3) spherical to ovoid cysts (29-35 μm long) without any surface attachment and a calcareous surface; and (4) spherical cysts (24-35 μm diameter) without any surface attachment and an organic surface. The first type of cysts was the most common: 77.70% and 95.18%, respectively, in the two different cultures. The cysts from sediments were primarily of the first type, which have calcareous attachment, and the fourth type, with an organic wall without any attachment, was infrequent. We discuss the reasons for the different morphology of S. trochoidea cysts produced during culture and the morphology of cysts from sediments.