Research Of Selenium Enrichment Characteristic And Speciation Distribution Im Peanut

Selenium,as an essential trace element in human body,has an important impact on human health.It not only has the functions of preventing cancer and anti-oxidation,but can also enhance human immunity.In nature,selenium mainly exists in the form of inorganic selenium and organic selenium.Compared with inorganic selenium,organic selenium has higher safety and availability.By applying inorganic selenium to plants or crops,the inorganic selenium can be transformed into organic selenium and enter the food chain,so that people can achieve the purpose of supplementing selenium safety.Peanut,known as"longevity fruit",is an important oil crop and cash crop in China.It not only has good nutrition and health care function,but also has a strong selenium-rich ability.Based on black peanut as the research object,three selenium application methods were adopted?selenium application on leaf surface,soil Se-supplement,common application of selenium on soil and leaves?,and explore different ways of applying selenium,different selenium concentrations on physiological characteristics of peanut,total selenium,selenium concentrations of each parts and peanut grain selenium content in selenium protein,selenium polysaccharide,protein,polysaccharide,selenium content in The organic selenium?C₄H₉NO₂Se?,selenium-methionine(C₅H₁₁NO₂Se)andselenium-cysteine(C₆H₁₂N₂O₄Se₂)as well as inorganic selenium in peanut were qualitatively and quantitatively analyzed by liquid mass coupling?HPLC-ESI-MS?under the selenium application in leaf surface,and the following conclusions were drawn:The emergence rate:foliar applied to selenium,applying selenium in soil,selenium was applied to both soil and leaf surface,at the same time on the leaf size of selenium concentrations have effects on germination rate of peanut,embodied in:peanut seedling emergence in 0.1².0 mg·L^-11 containing selenium medium,higher than the control group,when the selenium content of 2.0 mg·L^-1,reach peak emergence,but when the selenium content of 2.5 mg·L^-1,either way of selenium,emergence rate fell sharply.The plant height:under the three selenium application methods,The plant height of peanut increased first and then decreased with the increase of selenium concentration.For selenium application on leaf surface and combined selenium application on soil and leaf surface,the concentration of selenium enriched nutrient solution was between 0.1 mg·L^-11 and 2.0 mg·L^-1,and the plant height of peanut increased significantly,reaching the maximum at 2.0 mg·L^-1.And the effect of selenium application on leaf surface was slightly better than that of combined selenium application on soil and leaf surface.When the selenium concentration was greater than 2.0 mg·L^-1,the plant height of peanut began to decline with the increase of selenium concentration.Yield:application of selenium fertilizer can significantly increase peanut yield.Compared with the control group,the maximum yield of selenium application on leaf surface,soil Se-supplement,common application of selenium on soil and leaves can be increased by 30.1%,17.5%and 15.1%respectively.When the selenium application gradient was 2.5 mg·L^-1,the peanut yield reached the maximum when selenium application is applied on the leaf surface,soil,soil and leaf surface.As can be seen from the figure,selenium application on the leaf surface has the best effect in improving peanut yield,followed by selenium application in the soil and leaf surface,and the effect of selenium application in the soil was relatively poor.Chlorophyll content:the chlorophyll content in peanut leaves was different under three selenium application methods.Chlorophyll in peanut leaves with selenium application decreased with the increase of selenium application concentration,and the chlorophyll in peanut leaves with selenium application decreased by 29.8%compared with the control group.When selenium was applied to soil,chlorophyll content in peanut leaves increased substantially with the increase of selenium concentration.When selenium concentration reached 3.0 mg·L^-1,chlorophyll content reached the maximum,which is 32.4%higher than that of the control group.Peanut sample digestion conditions optimization results:a.Weigh 0.2 g peanut powder and add 5 mL HNO₃,the first step is 120°C,5 min,10 min,6 kw;the second step is 150°C,5 min,10 min,6 kw.b.Weigh 0.1 g of peanut leaves or shells and add4 mL of HNO₃ and 1 mL of HF.The digestion conditions are:first step is 100°C,5min,5 min,6 kw;second step is 120°C,5 min,15 min,6 kw.Selenium content in peanut seeds,peanut shells and peanut leaves was determined by hydride generation atomic fluorescence spectrometry.The results showed that under the same selenium concentration,selenium distribution in various parts of peanut was>peanut shell>stem and leaf,indicating that peanut seeds had a strong ability to enrich selenium.The selenium content in peanut grains increased with the increase of selenium application,but decreased after the selenium content exceeded 2.0 mg·L^-1.3)The effects of different selenium application concentrations on the relative contents of salt-soluble selenium are not obvious,while the other four forms of selenium have relatively large fluctuations under different selenium application concentrations.When the selenium concentration was 1.5mg·L^-1,the relative selenium content in the solution state,alkali solution state and acid solution state of Tris-HCl reached the maximum,which was 13%,37%and 18%respectively.However,when the concentration of selenium in water reached 1.0 mg·L^-1,the maximum value was reached,and the proportion of selenium in water was 25%.And the relative selenium content of these four forms appeared with the increase of selenium application concentration.The distribution of relative selenium contents in the five forms of selenium-rich peanuts is as follows:>in alkali solution>in water solution>in acid solution Tris-HCl in salt solution>in salt solution.At the low concentration of selenium gradient,the content of soluble protein and polysaccharide in peanut was increased with the increase of selenium concentration.Protein selenium content in peanut was much higher than that in polysaccharide selenium.When selenium concentration reached 1.5 mg·L^-1,protein selenium in peanut accounted for51.88%of the total selenium.When selenium concentration reached 0.5 mg·L^-1,the proportion of polysaccharide selenium in peanut was 10.21%.4)HPLC-ESI-MS combined technology was used to qualitatively and quantitatively analyze selenium-methyl selenium-cysteine,selenium-methionine,selenium-cysteine,sodium selenide and sodium selenide in selenium-rich peanuts.The content relationship was as follows:selenium-methyl selenium-cysteine>selenium-methionine>selenium-cysteine>selenium-selenite sodium>With the increase of selenium content,to a certain extent promoted the selenium methyl selenium cysteine,selenomethionine,selenium generation cystine and the content of selenium acid sodium,sodium selenite,and improves the selenium content of gradient on the selenium 2.0 mg·L^-1,Se concentration in Se-MeSeCys,Se-Met and Se-Cys₂ reached the maximum,which was 627.9?g·kg^-1,615.4?g·kg^-11 and 73.3?g·kg^-1,respectively.The highest Se content in Na₂SeO₄ was 11.0?g·kg^-1,and the highest Se content in Na₂SeO₃ was 2.9?g·kg^-1.Low levels of selenium can accumulate more organic selenium while high levels can slow down the conversion of inorganic selenium to organic selenium,resulting in selenium accumulation.