Effects Of Nitrogen Forms On Carbon-nitrogen Metabolism And Content Of Main Secondary Metabolites In Ginkgo Biloba

To study the effects of different forms of nitrogen fertilization on carbon and nitrogen metabolism and secondary metabolites content of Ginkgo biloba can provide theoretical basis for rational fertilization of Ginkgo biloba leaf forest.Using 1-year-old seedlings of Ginkgo biloba as materials,pot experiments in greenhouse were conducted to determine the growth,photosynthetic characteristics,carbon and nitrogen metabolism and major secondary metabolites of Ginkgo biloba under different treatments.Five different ammonium-nitrate ratios?m?NH₄⁺-N?:m?NO₃^--N??were set up,which were 100:0,75:25,50:75 and 0:100,respectively.The total nitrogen concentration levels were 1 g/pot,2 g/pot and 3 g/pot,respectively.The law of change.The main results are as follows:?1?With the increase of NO₃^--N ratio,the seedling height,ground diameter and biomass of Ginkgo biloba increased first and then decreased,and P4?ammonium-nitrate ratio 25:75?treatment was the highest.With the increase of total nitrogen concentration,seedling height,ground diameter and biomass increased first and then decreased,and M3?total mass concentration 1g/pot?treatment was the largest.M2P4?1g/pot-25:75?treatment had the best effect on seedling height,ground diameter and biomass.?2?With the increase of NO₃^--N ratio,Pn,Gs,Ci and Tr of Ginkgo biloba seedlings increased first and then decreased,and P4?ammonium-nitrate ratio 25:75?treatment was the highest.With the increase of total nitrogen concentration,Pn,Gs,Ci and Tr increased first and then decreased,and M3?total mass concentration 1g/basin?treatment was the largest.The effect of M2P4?1g/pot-25:75?treatment on basic photosynthetic parameters was significant.?3?With the increase of NO₃^--N ratio,the content of carbon metabolites and related enzymes in Ginkgo biloba seedlings increased first and then decreased.P4?ammonium-nitrate ratio 25:75?treatment was the highest.With the increase of total nitrogen concentration,the contents of total carbon,starch,sucrose,soluble sugar and the activities of AMS,SS and SPS increased first and then decreased,and M3?total mass concentration 1g/basin?treatment was the largest.M2P4?1g/pot-25:75?treatment had the best effect on promoting carbon metabolism.?4?With the increase of NO₃^--N ratio,the contents of nitrogen metabolites and related enzymes in Ginkgo biloba seedlings increased first and then decreased.P4?ammonium-nitrate ratio 25:75?treatment was the highest.With the increase of total nitrogen concentration,the contents of total nitrogen,soluble protein,free amino acid and the activities of NR,GS and GOGAT increased first and then decreased,and M3?total mass concentration 1g/basin?treatment was the largest.M2P4?1g/pot-25:75?treatment had the best effect on promoting nitrogen metabolism.?5?With the increase of NO₃^--N ratio,the content of main secondary metabolites in Ginkgo biloba increased first and then decreased.P4?ammonium-nitrate ratio 25:75?treatment was the highest.With the increase of total nitrogen concentration,the contents of quercetin,kaempferol,isorhamnetin,total flavonoids,polypentenol and the yield of flavonoids and polypentene increased first and then decreased,and M3?total mass concentration 1g/pot?treatment was the largest.M2P4?1g/pot-25:75?treatment had the best promotion effect on the main secondary metabolites.Mixed application of NH₄⁺-N and NO₃^--N enhanced the carbon and nitrogen metabolic ability of Ginkgo biloba and increased the content of main secondary metabolites.Under the current soil conditions,the ratio of NH₄⁺-N:NO₃^--N was 25:75,and the total nitrogen concentration was 2 g/pot,which had the best effect.It should be adjusted properly according to the actual situation in production.