| Caulerpa lentillifera is an edible large economic green algae with high nutritional value.Selenium as an essential trace element and has a great effect on the health of the human.Higher levels of selenium in the C.lentilliferaincrease its economic value.At present,intensive food selenium content to supplement human selenium feeding is currently a hot spot for functional food research,and economical large algae has only attracted attention in recent years in the enrichment of selenium.Therefore,in this experiment,sodium selenite(Na2SeO3)was added in the culture medium of C.lentillifera,and the selenium-enriching ability of algae and related factors were investigated.This study provides a theoretical basis for the subsequent cultivation of selenium-enriched seaweed food.The main results as follows:1.Effects of different selenium concentrations on the absorption capacity of selenium of the C.lentillifera,the results showed that the addition amount of sodium selenite was in the range of 0-8 mg/L.With the increase of selenium concentration,the selenium content(dry weight)of algae increased from 1.70μg/g to 50.10μg/g,When the concentration of selenium was more than 2 mg/L,the growth rate of the C.lentillifera was significantly decreased(P<0.05),the content of chlorophyll a and chlorophyll b was significantly decreased(P<0.05).There were no significant differences on the growth rate,chlorophyll a and chlorophyll b contents when the concentration of selenium was less than 2 mg/L.There was no significant change in carotenoid content among the experimental groups.Under lmg/L and 2mg/L concentrations of selenium,the enzymatic activities of Superoxide Dismutase,Glutathione Peroxidase and Catalase were increased.When the concentration of selenium was increased to 4 mg/L,the concentration of Reactive Oxygen Species was increased,the activity of GSH-PX and SOD increased again,but the activity of CAT decreased.2.Effects of different addition methods on the selenium enrichment of C.lentillifera.The results showed that under the one-time addition of selenium,the enrichment of selenium was the highest(18.58μg/g),which was significantly higher than other experimental groups(P<0.05).Followed by the method of adding in the last three days,the selenium content reached 16.30 ug/g,compared with other experimental groups,the difference was significant(P<0.05).However,there is no significant difference between the other three additiol methods.3.Changes of selenium content in C.lentillifera under different time.The results showed that under the condition of 2 mg/L sodium selenite,the selenium content of C.lentillifera increased with time,and the absorption capacity of selenium was fast in the first 16 h,reaching 7.77μg/g.After a while,the selenium enrichment of algae was relatively stable,and the total selenium content was kept on 8.00μg/g.4.Effects of temperature,light intensity and N/P ratio on selenium enrichment in C.lentillifera.The results showed that under the 2 mg/L condition of selenium concentration,the optimal combination condition for cultivating C.lentillifera were at 28℃,2000 1x and the N/P ratio of 10:1.The optimal selenium-rich conditions for algae were temperature 24℃,light intensity 2000 lx and N/P ratios 8:1.5.Effects of different light qualities on selenium enrichment in C.lentillifera.The results showed that under the condition of 2 mg/L selenium concentration,the growth was best under red light conditions,and the specific growth rate was the highest.Under blue light conditions,the selenium content of the algae was the highest(dry weight),reaching 12.44μ.g/g.The contents of chlorophyll a,chlorophyll b and carotenoid were higher in the experimental group of red,blue and white light.T-AOC was higher in the red and blue light experimental groups,and significantly different from the yellow light experimental group(P<0.05).The activity of T-SOD was higher in the red,blue and white light experimental groups,and significantly higher than green group(P<0.05).The total protein content in the blue light experimental group was the highest,which was significantly higher than other experimental groups(P<0.05).Soluble sugar was higher in the red and blue light experimental groups,and significantly higher than the yellow and green(P<0.05).The content of vitamin C in the red and white light experiments was higher,and there was no significant difference between the two groups,which was significantly higher than other experimental groups(P<0.05).6.Effects of different zinc concentrations on the zinc-rich of the C.lentillifera.The results show that with the increase of zinc concentration,the specific growth rate of algae decreased.The zinc concentration in the range of 0-8 mg/L,the zinc enrichment of the algae increased linearly with the zinc concentration.The zinc enrichment(dry weight)increased from 31.82 μg/g to 2.13 mg/g,nearly 70 times,and there was a significant difference between the groups(P<0.05).The content of chlorophyll a was the highest in the control group(0 mg/L),and the difference was significant compared with other experimental groups(P<0.05).The chlorophyll b content decreased with the increase of zinc concentration,and the difference between the groups was significant(P<0.05).For the carotenoid content,it increased first and then decreased,and the content in the 8 mg/L experimental group was the lowest,which was significantly different from other experimental groups(except the control group)(P<0.05).7.The effect of zinc-selenium interaction on the enrichment of zinc and selenium in C.lentillifera.The results show that,in the control group(Zn0Se0),the specific growth rate of algae was the highest.With the increase of zinc and selenium concentration,the growth of algae was gradually inhibited.In the control group(Zn0Se0),the content of chlorophyll a and chlorophyll b was the highest,which was significantly higher than other experimental groups(P<0.05).With the increase of zinc and selenium concentration,the content of chlorophyll a and chlorophyll b decreased,the content of carotenoid was the lowest in the control group(Zn0Se0).With the increase of zinc and selenium concentration,the content of carotenoids increased.Under the interaction of zinc and selenium,with the increase of zinc concentration,the zinc content(dry weight)of algae increased.The zinc enrichment of algae in the high concentration group was significantly higher than that of the low and middle experimental groups(P<0.05).Under the condition of high concentration of zinc,the enrichment ability of algae to zinc is enhanced with the increase of selenium concentration.In the low,medium and high concentration selenium experimental group,the selenium enrichment of algae increased with the increase of zinc concentration.Under the low concentration selenium(1 mg/L),high concentration of zinc was added,which increased the selenium content of the C.lentillifera.Under the medium concentration selenium(2 mg/L),adding different concentrations of zinc will increase the selenium enrichment of algae.Under the high concentration selenium(4 mg/L),adding zinc has no effect on the enrichmen of selenium by algae. |
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