摄食对球形棕囊藻囊体形成的影响

Effects of Grazing on the Colony Formation in Phaeocystis globosa

利用海洋尖尾藻摄食球形棕囊藻,研究摄食与球形棕囊藻生活史转换的关系。结果表明:海洋尖尾藻可大量摄食球形棕囊藻游离单细胞,摄食引发球形棕囊藻囊体直径显著增大。即使同海洋尖尾藻并未直接接触,球形棕囊藻依然可感受天敌摄食的信息,从而增大囊体直径。囊体直径增大是一种诱导性防御策略,为囊体细胞提供保护,可能是棕囊藻能够躲避浮游动物摄食而引发大规模藻华的重要机制。

Heterotrophic dinoflagellate Oxyrrhis marina was grazed by Phaeocystis globosa to determine the lifecycle alternation in Phaeocystis globosa as response to chemical cues released from grazing O. marina. Colony formation in P. globosa was enhanced in terms of colony size when solitary cells of P. globosa were grazed by O. marina extensively. Even without direct physical contact with O. marina to initiate the defensive response, P. globosa received chemical signals generated during grazing activities that stimulated an increase in colony size. Colony enlargement belongs to inducible defense strategy, which allows P. globosa to defend against grazers. Life-cycle transformations and colony formation as responses to grazing may contribute to the global success of Phaeocystis.