AUTHOR=Sun Jing , Chen Mingqiang , Fu Zhengyi , Yang Jingru , Zhou Shengjie , Yu Gang , Zhou Wenli , Ma Zhenhua 

TITLE=A Comparative Study on Low and High Salinity Tolerance of Two Strains of Pinctada fucata

JOURNAL=Frontiers in Marine Science

VOLUME=8

YEAR=2021

URL=https://www.frontiersin.org/journals/marine-science/articles/10.3389/fmars.2021.704907

DOI=10.3389/fmars.2021.704907

ISSN=2296-7745

ABSTRACT=<p>This study compares salinity tolerance between red and black shell <italic>Pinctada fucata</italic> salinity stress of 20 and 50‰, while 35‰ was used as a control. The hemolymph osmotic pressure, inorganic ion concentration, the activities of Na<sup>+</sup>-K<sup>+</sup> -ATPase, respiratory metabolism related enzymes and liver tissue antioxidant related enzymes were measured at 12 and 24 h after salinity stress. The osmotic pressure and inorganic ion concentration of hemolymph of two strains <italic>P. fucata</italic> increased significantly with the increase of salinity. The activity of Na<sup>+</sup>-K<sup>+</sup> -ATPase of red <italic>P. fucata</italic> only decreased under low salinity at 24 h, and was significantly higher than that the control under low salinity at 12 h and high salinity at 12 and 24 h. The succinate dehydrogenase (SDH) activities of the <italic>P. fucata</italic> treatment groups were significantly higher than those the control at 12 h. The lactate dehydrogenase (LDH) activity increased significantly with salinity at 12 h. and the black <italic>P. fucata</italic> LDH activity was significantly higher than the control at 24 h, while the LDH activity of red <italic>P. fucata</italic> was significantly lower than that the control in 50‰ salinity. The superoxide dismutase (SOD) activity of black <italic>P. fucata</italic> was significantly lower than that the control, while that of red <italic>P. fucata</italic> was significantly higher than that the control within 24. At 12 h, the catalase (CAT) activity of red <italic>P. fucata</italic> increased significantly with salinity, but decreased significantly with salinity at 24 h. The CAT activity of black <italic>P. fucata</italic> was highest at 24 h under low salinity. Glutathione peroxidase (GSH-Px) and alkaline phosphatase (AKP) activities of red <italic>P. fucata</italic> were significantly higher than those the control under low or high salinity. At high salinity for 24 h, the GSH-Px activity was lowest in black <italic>P. fucata</italic>, AKP activity was highest. The present study indicates that the physical responses of <italic>P. fucata</italic> to the salinity stress vary with shell colors. The red <italic>P. fucata</italic> can quickly respond positively to the change of environmental salinity and reduce the damage caused by the change of environmental salinity.</p>