Effects of temperature, irradiance and salinity on the growth of gametophyte and young sporophyte in Ecklonia kurome

Abstract

The effects of temperature, irradiance and salinity on the growth and survivorship of gametophyte and young sporophyte in Ecklonia kurome collected from the coast of Fukui Prefecture, were examined in laboratory culture. The upper critical temperature of gametophyte was 28℃ and that of young sporophyte was 26℃ . The optimal growth conditions at different temperature/irradiance levels were 22-24℃/50-100μmol/m²/s in female gametophyte, 20-22℃/100μmol/m²/s in male gametophyte, and 15℃/100μmol/m²/s in young sporophyte, respectively. The upper critical temperature for maturation of gametophyte was 22-24℃. The optimal growth conditions of gametophyte and young sporophyte at different temperature/salinity levels were 20-24℃/28-36 psu and 15℃/32 psu, respectively. The high maturation rates of female gametophyte were observed under the combination of 15-20℃ /24-32 psu. The significant decline of survivorship under high temperature and low salinity was observed at 24-28℃ in gametophyte and 22-28℃ in young sporophyte, respectively.