| The experiment studied the effects of the environmental factors of temperature, salinity, light intensity and nutrient concentration on growth, biochemical compositions, living conditions and uptake rates of Enteromorpha prolifera. It's provide a basic date to forecast the E. prolifera changing the sedimentary type to floating type.The alga cultured under the temperature of 10.0, 15.0, 20.0, 22.5, 25.0, 27.5, 30.0℃. The results showed that the RGR of E. prolifera exceeded 20% between 10-30℃, and had a maximum value of 29.57% at 25℃. When temperature was above 20℃, E. prolifera could change to be floating and the time will be shortened with the increase of the temperature. Temperature had a insignificant effect on chlorophyll content and tissue C and N.The experiment of the effect of salinity on the growth, biochemical compositions, living conditions and uptake rates of E. prolifera was compared under the salinity of 0, 5, 10, 15, 20, 25, 30. The result showed that the most appropriated salinity was 15-25. The living condition of E. prolifera changed at the salinity of 5-25. The chlorophyll a/b content was significant decearsed than other salinity, the value of chlorophyll a/b content was 0.399mg g-1, 0.238mg g-1.When the salinity was 30, the values of chlorophyll a/b content reached the maximum, which was 1.547 mg g-1, 0.793 mg g-1, respectively. The effects of salinity on tissue C and N of E. prolifera was not significant.The experiment of the effects of light intensity on the growth, biochemical compositions, living conditions and uptake rates of E. prolifera was compared under the light intensity of 20, 40, 80, 160, 320 and 400μmol·m-2·s-1. The result showed that the most appropriated light intensity was 320μmol·m-2·s-1 .The chlorophyll a / b content of E. prolifera was negatively correlated with light intensity. The maximum value was obtained under the light intensity of 20μmol·m-2·s-1, that was 3.15 mg g-1and 1.79mg g-1, separately. The minimum value was 1.19 mg g-1 and 0.49 mg g-1 under the light intensity of 400μmol·m-2·s-1. Light intensity had a insignificant effect on chlorophyll content and tissue C and N and their ratio.The experiment had four nutrient concentrations 0/0, 50/3.13, 100/6.25, 200/12.5μmol·L-1. The results show that the N/P concentration had a significant effect on relative growth rate of E. prolifera. The maximum chlorophyll content was in the highest N/P concentrations, which was 100/6.25μmol·L-1, when the N/P concentrations were 200/12.5μmol·L-1. NR activity increased with the increasing of the N / P concentration.Enviromental actors had a significant effect on the nitrate nitrogen uptake rates of E. prolifera. The uptake rate of the first 6 hours was higher than 12 or 24 hours later; E. prolifera had a higher uptake rate when the temperature was 20℃. The uptake rates of E. prolifera was positively related to salinity. The maximum uptake rates of E. prolifera was under the light intensity of 160μmol·m-2·s-1.In conclusion, E. prolifera was a plant which could bear a large range of temperature, salinity and light intensity. That's why E. prolifera could widely distribute everywhere all over the world. In addition, higher temperature and lower salinity can catch the sedimentary type to be floating type. It is the reason that green tide happened under the right condition. |
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