EARLY DEVELOPMENT, LIFE HISTORY, AND EFFECTS OF ENVIRONMENTAL FACTORS ON THE GROWTH AND DEVELOPMENT OF SPARLINGIA PERTUSA

Sparlingia pertusa, a species belonging to the order Rhodymeniales (Florideophyceae, Rhodophyta), is an invasive macroalga in China, originally from Russia and so far reported only in Dalian City. This alga inhabits the subtidal zone and is characterized by its large and leaf-like shape. It rapidly proliferates in the spring, significantly affecting the growth of native algal communities, making it an urgent target for control measures. However, the life history and growth conditions of S. pertusa remain unclear, posing important factors that impede its management. In order to effectively inhibit its growth and protect the ecological balance of the original ecosystem, we investigated the early development, life history, and effects of environmental factors on the growth and development of S. pertusa under laboratory conditions. The results indicated that: (1) S. pertusa exhibits a “direct discoid” type of spore development with the spores directly develop into discoid thalli through cell division; (2) Its life history includes isomorphic alternation of generations in gametophytes (haploid), carposporophytes (diploid), and tetrasporophytes (diploid). The gametophytes and tetrasporophytes are morphologically identical, exhibiting a characteristic isomorphic alternation of generations; (3) Temperature, light intensity, and salinity significantly influence the early development of S. pertusa. The optimal growth conditions were identified as a temperature of 11℃, a light intensity of 80 μmol phontons/(m²·s), and a seawater salinity of 30‰, with a suitable range being 8—14℃, 60—100 μmol phontons/(m²·s), and 20‰—40‰ salinity. This study elucidates the life history of the genus Sparlingia and identifies its optimal growth conditions, providing a theoretical basis for the future management of this species.