| In recent years, the treatment of salt water area has been plagued by everyone, and getting worse. There are many research on the treatment of salt water area, but mainly of them research from the perspective of water desalination treatment, there are some scholars started looking salinity vegetation, few scholars study the ecological balance from the perspective of the entire building. If we can exploring alkaline stress on aquatic ecosystems of key biological process- affect digestion feeding behavior and resistance response of Daphnia magna through experiments, we will achieve continuous factory training and accurately grasp the opportunity to put theoretical Daphnia magna foundation, but can be implemented in Daphnia magna is guided aquatic ecosystem restoration in saline area for a radical improvement in saline waters offers the possibility of contamination. In this paper, by simulating the saline environment, we can simultaneous determination of Daphnia heart rate, feeding rate, filtration rate in each treatment factor and the response of the digestive enzymes and antioxidant enzyme systems.The results and conclusions are as follows:1 The effects of different p H and salinity on Daphnia magna heart rate and feeding behavior(1) pH and salinity on two growth of Daphnia magna exhibited "low promote high suppression" trend, the adaptability of alkaline water is greater than the acidic water.The optimum p H and salinity about young and older Daphnia magna is respectively 6-8and 7-9, 2 and 3. the metabolism of young Daphnia magna is faster than older Daphnia magna and more sensitive to changes in p H and salinity,but the adaptability to adverse external environment is less than older Daphnia;(2) Young Daphnia magna’s heart rate is higher than the older, indicating that their metabolic activity is stronger than older, but its filtration rate and feeding rate is generally lower than older Daphnia magna. The changes of p H and salinity in young Daphnia magna are more sensitive than older ones, its adaptability to adverse external environment is less than older Daphnia.2 The effect of different p H and salinity on digestive enzyme activity(1) The activity of amylase in Daphnia magna is highest, is 6-8 times cellulase, is 10-12 times tryptase and pepsin. The content and activity of various enzymes is related with the diet of Daphnia magna;(2)The activity of amylase, cellulase, tryptase in Daphnia magna is greatly influenced by developmental stage, but the pepsin in Daphnia magna is not affected by developmental stages.(3) Daphnia magna digestive enzymes for p H and salinity of the stimulus has a certain sensitivity, combined with feeding rate can be found among older Daphnia magna p H8-9, salinity 3, young Daphnia magna at p H7-8, salinity 2 has a strong feeding and digestion. The optimum salinity on young Daphnia magna of feeding is 2, older ones is3.3 The effect of different p H and salinity antioxidant enzyme system(1) The body’s own antioxidant system can play a good role in maintaining normal body run when older Daphnia magna salinity within 5, among p H6-9, young Daphnia magna salinity within 3, among p H7-9;(2) There is a certain tolerance about the body’s defense system, after a long period of stimulation, the accumulation of reactive oxygen species and the amount of free radicals exceeds the capacity of the defense system, antioxidant enzyme activity decreased, the machine will suffer damage;(3)The tolerance of young Daphnia magna is less than older, young Daphnia magna to external stimuli with more sensitivity.(4)In order to achieve continuous culture of Daphnia magna, we should gradually increase the p H and salinity Daphnia magna according to developmental stages in the daily feeding process, which was adjusted to the optimum state.(5) In order to achieve rapid purification effect, in the actual application of aquatic ecosystems, we should elect to run at different stages of Daphnia magna to be targeted at different bodies of water. |
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