Physiological differences in the growth and maturation of Eisenia bicyclis and Ecklonia cava gametophytes in Korea

摘要

The objective of this study was to examine the effects of temperature and light intensity on growth of female gametophytes of Eisenia bicyclis and Ecklonia cava and responses of these female gametophytes to Fe addition and daylength. Female gametophytes of each species were cultured at four temperatures (10, 15, 20, and 25℃) and under a combination of four light intensities (10, 20, 40, and 80 μmol photons/(m2·s)) with two temperatures (15 and 20℃ for Ei. bicyclis; 20 and 25℃ for Ec. cava) to clarify their optimal growth conditions. Growth and maturation of female gametophytes of these two species under a combination of five Fe-EDTA concentrations (0, 1, 2, 4, and 8 μmol/L) and three daylengths (10, 12, and 14 h) were also examined. The growth of Ei. bicyclis gametophyte was maximal at approximately 15–20℃, 20 μmol photons/(m2·s), Fe-EDTA concentration of 8 μmol/L and daylengths of 12–14 h. While Ec. cava gametophytes showed optimal growth at approximately 20–25℃, 20 μmol photons/(m2·s), Fe-EDTA concentration of 8 μmol/L and daylength of 14 h. Maturation of gametophytes was enhanced at Fe-EDTA concentration of 4 μmol/L for Ei. bicyclis and at 2 μmol/L for Ec. cava. In conclusion, optimal growth temperatures and Fe-EDTA concentrations for maturation of Ei. bicyclis and Ec. cava gametophytes were different. Higher optimal growth temperature for Ec. cava gametophytes may contribute to its wider geographical distribution compared to Ei. bicyclis which has restricted habitats in Korea. This suggests that addition of Fe ion could be used to recover beds of these two species in barren grounds of Korea.