Effects Of Nutrient Elements On The Growth Of Ginkgo Biloba Seedlings And The Content Of Flavonoids In Ginkgo Biloba

Ginkgo biloba L.is a perennial tree of Ginkgo family.It is a landscape economic tree that integrates landscape,food,health care,medicine and scientific research.The medicinal value of Ginkgo biloba leaves has been paid attention to.The flavonoids and terpene lactones in the extracts of Ginkgo biloba leaves have been used for the treatment of diseases.The effects of major elements（nitrogen,phosphorus,potassium）,trace element boron and lanthanum on growth index,physiological index and flavonoids content in leaves of Ginkgo biloba were studied by pot culture,and the rule of nutrient requirement of Ginkgo biloba was discussed.In order to provide theoretical basis for rational fertilization of Ginkgo biloba,the following conclusions are obtained:1.The growth of Ginkgo biloba can be significantly promoted by the treatment of nutrient element combinations.The results showed that the growth of Ginkgo biloba was the best with the application of N 4320mg/L,P₂O₅720mg/L,K₂O 480mg/L,B 240mg/L,and La 50mg/L,and the accumulation of substances above and below the ground was significantly increased under the treatment.Compared with the control treatment,leaf biomass increased by 25.97%,leaf dry rate increased by 19.89%,specific leaf area decreased by 17.41%,root surface area increased by 16.84%.The effects of different elements on each growth index were different.Nitrogen had the greatest effect on the growth of Ginkgo biloba at the experimental level,which could increase leaf biomass,leaf drying rate,root drying rate,and decrease specific leaf area,etc.The growth of Ginkgo biloba was inhibited with the increase of potassium concentration.Low concentration of rare earth lanthanum（La 25⁵0 mg/L）and trace element boron（B 60²40mg/L）promoted the growth of Ginkgo biloba,and phosphorus only had significant effects on plant height increment and root surface area.2.The effects of different treatments on different physiological indexes were slightly different,and the order of effect of each element on different indexes was also different.The highest chlorophyll content of Ginkgo biloba was obtained by applyingN 1080mg/L,P₂O₅90mg/L,K₂O 960mg/L,B 240mg/L and La 200 mg/L,which was 67.12%higher than that of the control treatment.The order of effect of each element was N>B>La>K>P.The content of soluble sugar in Ginkgo biloba was the highest by applying N 2160mg/L,P₂O₅360mg/L,K₂O 480mg/L,B 120mg/L andLa 200mg/L,which was 28.47%higher than that of the control treatment.The effect order of each element was La>K>N>B>P.All treatments could increase the content of soluble protein in Ginkgo biloba leaves,andcompared with the control treatment,the maximum increase was 151.18%.With the increase of nitrogen and potassium concentration,the soluble protein content increased first and then decreased.When treated withN 540 mg/L,P₂O₅90 mg/L,K₂O480 mg/L,B60mg/L,La 25mg/L,the root activity was the strongest,which was 38.92%higher than that of the control treatment.The effect order of each element was N>B>P≈K>La.3.The content of flavonoids in Ginkgo biloba leaves could be increased by the combination of nutrient elements.The highestlevels of kaempferol,quercetinand total flavonoids were found in the treatment with N 1080mg/L,P₂O₅180mg/L,K₂O 480 mg/L,B480mg/L and La100mg/L,which was significantly higher than the control treatment,the increase was 31.43%,78%and 53.49%respectively.The effect order of each element was N>B>P>K>La.With the increase of nitrogen concentration,the content of flavonoids in Ginkgo biloba leaves increased first and then decreased.Middle and high concentrations of boron（B 60⁴80mg/L）and phosphorus（P₂O₅180⁷20mg/L）were more favorable to the accumulation of flavonoids in Ginkgo biloba leaves.While potassium and lanthanum had no significant effect on flavonoids content in Ginkgo biloba leaves.In conclusion,reasonable combination of nutrient elements can promote the growth index,physiological index and flavonoids content in leaves of Ginkgo biloba.In the early stage of ginkgo growth,attention should be paid to the supplement of nitrogen fertilizer and potassium fertilizer,and a certain amount of lanthanum should be added to promote the healthy growth of the above-ground and underground parts of Ginkgo biloba plants,so as to ensure good viewing and increase the yield of ginkgo biloba.In the late growing stage of ginkgo biloba,the application of nitrogen fertilizer can be reduced properly,the application of phosphorus andboron can be increased,the production of flavonoids of ginkgo biloba can be promoted,the quality of ginkgo leaves can be improved,so as to enhance the function ofginkgo.