Response Of Navicula Growth And Movement On Cu²⁺ Acute Stress

The researches of using diatom monitoring water pollution of Cu2 +, many relate experiments of Navicula tenera reported were focused on it as bait,and the research in aquaculture. The view of the Cu2 + movement over N.tenera toxicity effect and stress studies were rare. Through this study found that the Navicula has a unique advantage in indicating and testing aquatic pollution of Cu2 +.This study choose（N.tenera） as the subjects, studied the growth and movement characteristics under the stress of different concentration of Cu²⁺. Explored the N.tenera toxicity response of Cu2 + by stress growth of Cu2 +, chlorophyll a content and comprehensive movement index. The main results were as follows:1. The acute toxicity stress of Cu2 + had distinct effect on the growth of N.tenera.24 h had low concentration（1.5, 2.5 mg. L- 1）, the N.tenera to Cu2 + stress performance was born long excited "poisoning", the inhibition rate was 2.44%. EC50 72 h and 96 h EC50 were 3.583 mg. L- 1 and 4.510 mg. L- 1.The results showed that with the increase of the time, the ability to adapt to Cu²⁺ stress of N.tenera was improving;2. Used the quality concentration of chlorophyll a as an index, after 15 days training, the low concentration of Cu2 +（0.56375 mg. L- 1, 1.1275 mg. L- 1） was relatively stable during the period of 1 d 9 d change,3. N.tenera showed adaptability to some lower concentration stress of Cu2 +; Especially after 3 d, in High concentration（2.255 mg. L- 1, 4.51 mg. L- 1）, inhibition of chlorophyll a content accumulation phenomenonof N.tenera to Cu2 + is more obvious.4. The influence of toxicity stress of Cu2 + on movement of N.tenera.（1） the influence of Cu2 + to movement diatoms number in the the ratio of the total number of diatom. the change is relatively stable in Lower Cu2 + concentration（0.56375 mg. L- 1, 1.1275 mg. L- 1） during the 1 d 9 d, N.tenera showed some adaptability to lower Cu2 + concentration stress; In addition to the 1 d,Cu2 + high concentration（2.255 mg. L- 1,4.51 mg. L- 1） the number of sports diatom ratio appear significantly lower phenomenon, provided a possibility that using moving N.tenerain indicating Cu2 + high concentration in water;（2） the Cu2 + affected diatom average speed. Through the cultivation of 15 d, with the fastest speed as an index, changes in the rate of 1 3 d, were stable.at both ends were similarity, the middle was volatile;（3）The Cu2 + effects on N.tenera the fastest speed. Through the cultivation of 15 d, with the fastest speed as an index, 1 d and 15 d speed change is obvious, the other overall speed with incresing by mass concentration in 0.563 75 mg/L and 1.127 mg/L along concentration of Cu2 + and increase, decreased near to 2.255 mg/L. But in 4 d, 1.1275 mg/L and 11 d, 0.563 75 mg/L showed 2 abnormal speed respectively reached 0.8, 1.03 mu m/s, speed significantly decreased.In conclusion, It was a comprehensive and complicated physiological process of the influence of Cu2 + stress on N.tenera growth, photosynthesis and the movement process. Using N.tenera as a indicator to reflect the degree of water polluted by Cu2 + has certain feasibility. At the same time can provide basis for monitoring and evaluating agricultural, industrial and domestic sewage of Cu2 +.