Enrichment Of Nano-selenium In Fagopyrum Dibotrys And Its Effects On The Yield And Active Substances

Selenium(Se)is an essential trace element for humans and animals.About 72% of people in China are deficient in Se.The main resource of Selenium in food comes from plants.Suitable concentration of Se is not only beneficial to plant growth,but also can increase the metabolism of plant active substances and improve plant quality.Nanoselenium is a new type of selenium supplement because of its high biological activity,low toxicity and low environmental risk.Se-rich Chinese medicine has gradually become a hot topic with the increasing attention of Chinese herbal medicines by domestic and foreign scholars.In this study,the Se-enrichment ability of the main Chinese medicinal materials in the western Hunan and the Se distribution in the rhizosphere soil were analyzed,and Fagopyrum dibotrys,a Chinese medicinal material with strong bioaccumulation capacity for selenium,was screened out.This research found the relationship between Se enrichment and active substance content in F.dibotrys,which could help to develop and utilize the F.dibotrys resources better.In this paper,the F.dibotrys was used as the test material to study the effects of selenium enrichment on nano-selenium and sodium selenite,yield,the antioxidant enzyme activity and total flavonoids content in F.dibotrys.The aim of this research is to provide theoretical basis and practical guidance for the scientific planting research of seleniumenriched F.dibotrys.The main results are as follows:(1)The Se content in the 9 kinds of Chinese herbal medicines and rhizosphere soil of Xiangxi was analyzed.The Se content in 9 kinds of Chinese herbal medicines with roots and stems in the North Xiangxi were found in the order: F.dibotrys(1.01 mg/kg)> Fritillaria(0.35 mg/kg)> Rhubarb(0.25 mg/kg)> Polygonatumodoratum(0.24 mg/kg)> Polygonatumsibiricum(0.20 mg/kg).The Se content in Euphrasia pectinata Ten(1.29 mg/kg)> Hypericum attenuatumChoisy(1.17mg/kg)> Liparis nervosa(0.90 mg/kg)> Saxifraga stolonifera Curt(0.54 mg/kg),according tothe Standard of Selenium-enriched Agricultural Products in Hunan Province,the standard for seleniumenrichment agricultural products is > 0.15 mg/kg.F.dibotrys and Euphrasia pectinata Ten which are used as the roots and whole plant were found significantly rich with Se,which is a suitable for the cultivation of Se-enriched Chinese herbal medicines.(2)The exogenous Se absorption and enrichment ability of F.dibotrys were investigated,and found that foliar application of nano-selenium and sodium selenite could significantly increase the Se content in different parts of F.dibotrys.The Se accumulation in leaves,stems and massive roots of F.dibotrys was significantly correlated with the concentration of Se supplied.The distribution of Se in leaves was much higher than in roots.The bioconcentration factors of nano-selenium in the leaves,stems and massive roots of F.dibotrys in the 5 mg/L treatment group were 1.4 times,2.1 times and 1.3 times higher than sodium selenite treatments,respectively.The Se accumulation in leaves,stems and massive roots of F.dibotrys was significantly higher under foliar of nano-selenium treatments than foliared with sodium selenite.And Se absorped by F.dibotrys was partially transformed into organic Se speciesin leaves and roots.(3)The effect of Se on the biomass and active compounds in Se treated F.dibotrys were studied.We found that the biomass,antioxidant enzyme activity,photosynthetic pigment content and total flavonoid content of different parts of F.dibotrys increased first and then decreased with the increasing of Se concentration foliar on plants.Se treatment(5 mg/L)significantly inhibited the growth and accumulation of active components of F.dibotrys.The suitable concentration of Se could promote the growth and active substances in F.dibotrys.Compared with the control,the biomass of leaves,stems and roots under 5 mg/L selenium-nano treatment were increased by 78.87%,229.04% and 72.04%,respectively.In addition,the three antioxidant enzyme activities(POD,GSH-Px and SOD)increased by 161.94%,430.77%,and 90.48%,respectively;photosynthetic pigment(chlorophyll a,chlorophyll b)increased by 36.57% and 47.56%,respectively;the total flavonoid content of leaves,stems and massive roots increased by 157.48%,131.14% and 234.12%,respectively in nano-selenium treatment compared with control.In 5 mg/L sodmiun selenite treatment,the biomass of leaves,stems and lumps was increased by 34.49%,85.15% and 42.65%,respectively.The three antioxidant enzyme activities(POD,GSH-Px and SOD)increased by 46.11%,494.87% and 76.19%,respectively.The photosynthetic pigments chlorophyll a and chlorophyll b increased by 41.64% and 74.81%,respectively.The total flavonoids content in leaves and stems increased by 68.50% and 48.71%,158.79% respectively,compared with control.Foliar with5 mg/L nano-selenium increased the yield and flavonoid content of F.dibotrys by 1.2 times and 2 times,respectively,and the antioxidant enzyme activity of F.dibotrys was significantly higher than that under sodium selenite treatment.(4)In the field experiment,foliar application of Se in plants significantly increased Se accumulation in different growth organs of leaves,stems and roots in F.dibotrys,and significantly increased its yield compared with the control.Folair with Se can be used as an effective method for selenium-enriched cultivation for plants.The F.dibotrys can be used as a good selenium-enriched Chinese medicinal material.The concentration of Se in different organ parts of the F.dibotrys increased significantly with Se supplication.And there is no inhibition of Se supplied at 20 mg/L.The content of active substances in leaves,stems and roots of F.dibotrys increased first and then decreased with the increasing of Se concentration.The suitable concentration(5 mg/L)of nano-selenium and sodium selenite could significantly enhance the yield of F.dibotrys.The content of active substances,was significantly higher in nanoselenium treatment than that of sodium selenite treatment at the same concentration.The yield,antioxidant enzyme activity,total flavonoids content and chlorophyll content increased significantly compared with foliar with sodium selenite.Therefore,nanoselenium is a kind of low-toxic and high-efficiency selenium source than sodium selenite,and F.dibotrys can be further developed as a concentrate of concentrated Se.The combination of Se and F.dibotrys has great potential for development.The bioorganization of inorganic Se is carried out by using F.dibotrys as a carrier to explore the enrichment of nano-selenium by F.dibotrys and its effect on the yield and active substance content,which laid a theoretical foundation for the subsequent cultivation of Se-rich F.dibotrys and the development of special selenium-rich F.dibotrys products.