Allelopathy of the raphidophyte Heterosigma akashiwo against the dinoflagellate Akashiwo sanguinea is mediated via allelochemicals and cell contact

Marine Ecology Progress Series

Takuya#xa0Etoh¹  Tsuneo Honjo¹  Yuji Oshima¹  Tadashi Matsubara¹  Masato Honda¹  Mayumi Kawaguchi¹  Hiroaki Gunjikake¹  Shigeaki Matsui¹  Yasuhiro Yamasaki¹  Sou Nagasoe¹  Xuchun Qiu¹  Yohei Shimasaki¹ 

关键词: Heterosigma akashiwo;    Akashiwo sanguinea;    Allelopathy;    Polysaccharide−protein complex;    Cell contact;    Growth interaction;    Growth simulation;   

DOI  :  10.3354/meps09476

学科分类：海洋学与技术

来源: Inter-Research

【 摘 要 】

ABSTRACT: Growth interactions between the raphidophyte Heterosigma akashiwo and the dinoflagellate Akashiwo sanguinea were examined by using bi-algal culture experiments under axenic conditions. There was a lethal effect of H. akashiwo (initial cell density: 1 × 10² or 1 × 10⁴ cells ml⁻¹) on A. sanguinea at an initial cell density of 1 × 10² cells ml⁻¹. Growth of both species was suppressed concurrently when initial cell densities of H. akashiwo and A. sanguinea were 1 × 10² and 2 × 10³ cells ml⁻¹, respectively. A mathematical model was used to simulate growth and interactions in bi-algal cultures. The model predicted that H. akashiwo would outcompete A. sanguinea over time. A cell-free enriched filtrate prepared from dense culture of H. akashiwo reduced both maximum growth rate and maximum yield of A. sanguinea. A filtrate of A. sanguinea prepared in the same manner only reduced maximum yield of H. akashiwo but did not affect its maximum growth rate. Growth of A. sanguinea in bi-algal cultures under contact conditions was significantly lower than that in mono-algal culture and in bi-algal cultures under non-contact conditions. Morphologically abnormal A. sanguinea cells occurred at high frequency only when A. sanguinea was cultured together with H. akashiwo under direct cell contact condition. Moreover, growth inhibition and formation of morphologically abnormal cells of A. sanguinea were induced in a concentration-dependent manner by allelochemicals (including allelochemical polysaccharide−protein complexes) produced by H. akashiwo. These results suggest that growth inhibition effects, via allelochemicals and direct cell contact by Heterosigma akashiwo, influence bloom formation of Akashiwo sanguinea in the field.

【 授权许可】

Unknown