| Caulerpa lentillifera is an edible large green algae with high nutritional value.It is rich in many nutrients needed by the human and has important economic value in food and medicine.Iron is one of the essential trace elements in human.It not only plays an important physiological role in the cell metabolism of human,but also plays a restrictive factor in the process of photosynthesis and respiration of algae.Dietary iron supplementation is the most important way for Chinese residents to supplement iron.At present,the enhancement of biological crops is mainly in terrestrial plants,and it is late in macroalgae.Therefore,this study researches algae rich iron and iron rich after exploration on the physiological and biochemical changes by adding two different valence state of inorganic iron(Fe2+and Fe3+)in the process of Caulerpa lentillifera cultivation.By changing the light quality and adding two kinds of essential trace elements zinc,selenium interaction experiment,the researcher hopes to produce high value-added Caulerpa lentillifera,for subsequent algae of element enrichment mechanism and function of iron rich algae provide certain theoretical basis for the development of algae.The research results are as following:1.Effects of Fe2+ and Fe3+ on growth,iron content and physiological characteristics of Caulerpa lentillifera.The results showed that the inorganic iron in the two valence states had significant effects on the growth,iron content and physiological characteristics of C.lentillifera in the range of 0-12 mg/L after7 days of culture.When Fe2+concentration was 3 mg/L and Fe3+ concentration was 6 mg/L,the SGR of algae reached the maximum and significantly increased compared with the control group(p<0.05).Inorganic iron mainly had a significant effect on the contents of chlorophyll a and carotenoids in C.lentillifera(p<0.05),but had no significant effect on the contents of chlorophyll b(p>0.05)With the rise of iron concentration,the iron content of the algae also increased.When the concentration was 12 mg/L,the maximum iron content of the algal reached the maximum value.At this time,the maximum iron content under Fe2+treatment was 1522.540 ?g/g,which was 1369.34%higher than that in the control group(103.62 ?g/g).Under the treatment of Fe3+,the maximum iron enrichment was 1373.932?g/g with an increase of 1225.92%.In addition to 3 mg/L Fe3+,adding two kinds of inorganic iron can significantly increase the activity of T-SOD and CAT in algae(p<0.05).Fe2+ can significantly increase the VC and soluble sugar Fe3Se3 content of algal,while Fe3+ can only significantly promote VC(p<0.05).The total protein content of algal body decreased significantly after iron treatment(p<0.05).2.Effects of different light quality on the growth and the iron content of Caulerpa lentillifera.The results showed that when Fecl3 was used as the iron source and the concentration was 6 mg/L,after 7 days of culture,the three light qualities had no significant effect on SGR and photosynthetic pigment content of algae(p>0.05),but significant effect on the iron content of C.lentillifera(p<0.05).Under white light treatment,the highest iron content of algae was 564.180 ?g/g.The second is red light,which is 335.555 ?g/g.The least amount of iron in the algal body under blue light was 252.625 ?g/g,and the order of iron rich in different light quality treatment is white light>red light>blue light.3.Effects of iron and zinc interaction on the growth,iron content and zinc content of Caulerpa lentillifera.The results showed that ferric chloride(FeCl3)was used as the iron source and zinc sulfate(ZnSO4)as the zinc source.After 7 days of interaction culture of iron and znic,only Fe1Zn2,Fe2Zn1 and Fe3Zn1 of the experimental SGR significantly increased compared with the control group Fe0Zn0(2.888%·d-1)(p<0.05).Among them,the SGR of Fe3Zn1 is the highest,which is 3.897%·d-1.The interaction of iron and zinc had no significant effect on the photosynthetic pigment content of C.lentillifera(p>0.05).The iron content and zinc content of all the experimental groups significantly increased(p<0.05).When the iron concentration was constant,the amount of iron and zinc in the alga increased with the increase of the added zinc solution.The highest iron rich group was Fe3Zn3,and the concentration was 1049.194 ?g/g,which increased by 1836.97%compared with the control group(54.167 ?g/g).The highest zinc rich group was Fe1Zn3,and the zinc rich group was 381.037 ?g/g,which was 1304.12%higher than the control group(27.137 ?g/g).4.Effects of iron and selenium interaction on the growth,iron content and selenium content of Caulerpa lentillifera.The results showed that ferric chloride(FeCl3)was used as the iron source and sodium selenite(Na2SeO3)as the selenium source.After 7 days of interaction culture of iron and selenium,all the experimental groups except that Fe1Se3 and Fe2Se1 could significantly promote the growth of C.lentillifera(p<0.05).The SGR of the Fe2Se3 experimental group was the highest,which was 3.470%·d-1,increase of 307%compared with the control group.The interaction between iron and selenium had a significant effect on chlorophyll b and carotenoids.With the increase of iron and selenium concentration,the content of the two pigments decreased significantly(p<0.05).For the content of chlorophyll a,the change of the content of iron and selenium had little effect on the content of pigment at low iron concentration(6 mg/L)(p>0.05),and the content of pigment decreased significantly with the increase of the concentration of iron and selenium in middle iron(9 mg/L)and high iron(12 mg/L)(p<0.05).After the exchange culture of iron and selenium,all the experimental groups could significantly promote the absorption of iron and selenium by algae(p<0.05).Under the condition of low iron(6 mg/L),the iron content of algal decreased but was still higher than that of the control group,and the amount of algal enriched with selenium increased.Under the conditions of medium iron(9 mg/L)and high iron(12 mg/L),the contents of both iron and selenium in the algal increased with the increase of selenium concentration.Among them,the Fe3Se2 group had the highest iron content,which was 1354.400 ?g/g,increase of 2288%compared with the control group(56.711 ?g/g).The selenium content of Fe3Se3 in the highest group was 30.658 ?g/g,increase of 5123%compared with the control group(0.587 ?g/g).5.Effects of iron,zinc and selenium interaction on growth,element enrichment and enzyme activity of Caulerpa lentillifera.The results showed that ferric chloride(FeCl3),zinc sulfate(ZnSO4)and sodium selenite(Na2SeO3)were selected as the iron source,and the three factors and three levels of the orthogonal experiment were adopted.After 7 days of culture,when Fe:12 mg/L,Zn:0.5 mg/L and Se:4 mg/L,the algal of SGR was the largest and iron was the determining factor of SGR.For photosynthetic pigment content of algae,zinc has the greatest effect on the synthesis of chlorophyll,while selenium mainly affects the synthesis of carotenoids.When Fe:9 mg/L,Zn:0.5 mg/L,and Se:1 mg/L,the content of chlorophyll a and carotenoids in the algal body was the highest,and when Fe:6 mg/L,Zn:0.5 mg/L,Se:1mg/L,the content of chlorophyll b in the algal body was the highest.Different combinations have different effects on the enrichment amount.The optimal iron-rich combination should be Fe:12 mg/L,Zn:2 mg/L,Se:2 mg/L.The optimal zinc rich combination should be Fe:6 mg/L,Zn:2 mg/L,Se:2 mg/L.The optimal se-rich combination should be Fe:6 mg/L,Zn:2 mg/L,Se:4 mg/L.The optimal combination of total protein,T-SOD,CAT and MDA contents is also different,and the main influencing element is selenium.The optimal total protein combination should be Fe:9 mg/L,Zn:2 mg/L,Se:2 mg/L.The optimal combination of T-SOD should be Fe:6 mg/L,Zn:0.5 mg/L,Se:1 mg/L.The optimal combination for CAT should be Fe:9 mg/L,Zn:1 mg/L,Se:4 mg/L.The optimal combination for MDA should be Fe:9 mg/L,Zn:2 mg/L,Se:l mg/L. |
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