Validation Of Cultured Diatom Stressed By Heavy Metal

Heavy metal pollution of water environment has been one of the focus of the global environmental problems. Diatom is a good indicator monitoring water environment change, a single diatom is extremely sensitive to the change of water environment, has the very good instruction effects.In order to determine the diatom effect of heavy metal intimidation, to find the right diatoms as a biological monitoring of water environment of material, this study selected husk diamond algae(Nitzschia palea) as the experimental effects, using micro pipette separation to cultivate algae samples separately, got the husk of pure diamond algae, and use the soil leachate, f/2 medium, medium(NP) and development of medium to cultivate algae, morphological identification and molecular biology, two methods are used to determine the diatom species.With different concentration of Cd2+, Cu2+ for Nitzschia palea coercion, observation of algal surial, speed variation, chlorophyll a content and form.From algae and algae cell structure and physiological research of the toxicity effect of heavy metal, found Nitzschia palea can obviously reflect Cd2 +, Cu2 + on the effect of stress, thus suggests that Nitzschia palea have monitoring water pollution of heavy metals Cd2 +, Cu2 + potential. Different heavy metal stress effect of different algae, diatoms of other can also be through the method to determine the heavy metal stress effect on algae.The main results were as follows:1. Cd2+ stress effects Nitzschia palea of the effect, the acute toxicity experiment, with the increase of concentration and stress incubation time Cd2+ for Nitzschia palea enhanced growth inhibition. Nitzschia palea surial in 96 h EC50 value of 4.989 mg/L; Subacute toxicity stress experiment, training after 15 d Cd2+ concentration is 0.625, 0 mg/L of Nitzschia palea movement average velocity were 2.5, 5.56 μm/s, Cd2+ concentration is greater than 0.625 mg/L group show no sign of movement; Train after 15 d, Cd2+ concentration and chlorophyll a content showed a negative correlation(r = 0.764, P < 0.05), the regression equation for y = 0.251 + 4.782 x. By scanning electron microscope after incubation Nitzschia palea Cd2 + stress immediate vicinity of the surface structure change significantly, the number of body surface hole to reduce with the increase of the concentration of Cd2 +, in appearance on the contour and the concave.2. Cu2+ stress effects Nitzschia palea immediate vicinity of the effect, in the experiment of acute toxicity, Cu2+ for Nitzschia palea stress train 96 h EC50 was 0.895 mg/L, and low concentration of Cu2+ promote growth, high concentration inhibit the growth of algae; Subacute toxicity experiments, training after 15 d Cu2+ concentration was 0.112, 0 mg/L Nitzschia palea movement average velocity were 2.75, 5.56 mu m/s, the rest of the group show no sign of movement.;Train after 15 d, Cu2+ concentration and chlorophyll a content showed a negative correlation(r = 0.864, P < 0.05), the regression equation for y = 0.053 + 1.03 x. By scanning electron microscope after incubation Nitzschia palea Cd2+ stress in the immediate vicinity of the submicroscopic structure, found that the number of its surface hole decrease with the increase of concentration of Cu2+, and have sag in appearance on the contour.3. Different concentration of Cd2+, Cu2+ for Nitzschia palea of the growth, movement speed, had significant effect on the chlorophyll a content and form, and these data can be used as a biological monitoring information effects added.4. Found in NP medium for Nitzschia palea training can obtain more number of this kind of algae that it is more suitable for Nitzschia palea culture.5. By optical microscope and scanning electron microscope identification, and extract the effects of molecular identification of 18 srdna, two kinds of methods consistent experimental effects are determined for the grain and the diamond algal Nitzschia palea immediate vicinity.