Effects Of Environmental Factors On The Osmoregulation Of Eriocheir Sinensis

The paper studies the characteristic of the gill Na⁺-K⁺-ATPase of Eriocheir sinensis firstly, then based on the datum obtained, the specific activity of the enzyme, hemolymph ions concentrations and hemolymph osmolality are choosen as the targets to study the effects of different salinity, Na⁺/K⁺ ratio, pH and alkalinity on the osmoregulation of Eriocheir sinensis systematically. The main results of the study are as follows:1. The optimum reaction temperature of Na⁺-K⁺-ATPase is 40℃, and the activity of the enzyme drops rapidly when the temperature is higher than 45;℃ The optimum reaction pH value is 8 and the activity of the enzyme is very sensitive to pH, and the activity of the enzyme drops rapidly when the value of the pH is lower than 7.5 or higher than 8.25. The activity of Na⁺-K⁺-ATPase is completely restrained when the concentration of the ouabain reaches 2mmol/l; The optimal concentration of ATP-Nai, Na⁺,K⁺and Mg²⁺ in the reaction medium is. 1.5 ,75 ,15, 6mmol/l respectively. The Na⁺-K⁺-ATPase activities of the posterior three pairs of gills are higher than the anterior five pairs of ones evidently.2.The hemolymph osmolality and hemolymph ion concentrations increase, and the total protein of hemolymph decreases little when the value of the salinity increases from 0 to 16, in this range of the salinity, the activity of Na⁺-K⁺-ATPase decreases distinctly. The changes of these targets are not at the same time, the hemolymph osmolality and hemolymph ions concentrations increase after 3 hours of the salinity infection, however the total hemoprotein and the activity of Na⁺-K⁺-ATPase decreases 6 hours later, all the values of targets keep stable from the 3rd day to the 15th day3. Na⁺/K⁺ ratio of water is an important factor that affects the activity of Na⁺-K⁺-ATPase, hemolymph osmotic pressure and hemolymph iqns concentrations.The: activity, of Na⁺-K⁺-ATPase, hemolymph sodium concentration arid hemolymph osmolality decrease, while hemolymph potassium concentration increases when the Na⁺/K⁺ ratio is lower thanl .07 or higher than 31.63.4. It can cause activity of Na⁺-K⁺-ATPase, hemolymph osmotic pressure and hemolymph sodium concentration to decrease and the hemolymph potassium concentration to increase when the value of pH is 4.5 and 5.5, however when the pH is 6.5 and 9.5 it have no influence on the activity of Na⁺-K⁺-ATPase, hemolymph osmotic pressure and hemolymph ions concentrations, the influence degree of pH 6.5 and 9.5 is the same as suitable pH 7.5 and 8.5 of Eriocheir sinensis.5.When the alkalinity value of water is 10.36, 15.52, 21.06 mmol/1, it can cause Na⁺-K⁺-ATPase activity, hemolymph osmolality and hemolymph sodium concentration to decrease and the hemolymph potassium concentration to increase, and the influence is more acutely when the value of the alkalinity raise; However when the alkalinity value of water is 1.70 and 5.97 mmol/1, it have no acute influence on the osmoregulation of Eriocheir sinensis.