Effects Of N,P,K And Mo On The Growth And Quality Of Platycodon Grandiflorum(Jacq.)A.dc.

Platycodon grandiflorum(Jacq.)A.DC is a traditional Chinese medicine.The root can be used as medicines with the effects of ventilating lung,relieving cough and expelling phlegm.P.grandiflorum can also be used for edible and ornamental.Its development prospects sprawling as the functional food.Because of the problems such as poor yield,quality and economic efficiency caused by the influence of fertilization techniques in cultivation of Platycodon grandiflorum,the pot culture experiment was conducted to study the effect of nitrogen,phosphorus,potassium on the growth and quality of Platycodon grandiflorum.The treatments based on different nitrogen forms combined with molybdenum were designed for discussing the promoting effect of molybdenum on nitrogen absorption and utilization of Platycodon grandiflorum.Results are as follows:1.The activity of NR increased with the increasing of NO3--N in the leaf and root of Platycodon grandiflorum under different nitrogen forms treatments.The activity of GS increased and then decreased with the increasing of NO3--N in the leaf,but increased with the increasing of NH4+-N in the root.The content of nitrate nitrogen and ammonium nitrogen increased and then decreased with the increasing of NO3--N in the leaf and roots.The total chlorophyll contents and Pn were the highest at the NH4+-N/NO3--N ratio of 75:25.Different nitrogen forms and ratio was beneficial to increase the activity of SOD,CAT,POD and decrease the MDA content in the leaf of Platycodon grandiflorum.2.The nitrate accumulation increased constantly during the cultivation process of P.grandiflorum.In contrast,the nitrite accumulation decreased during the cultivation process of P.grandiflorum.When NH4+-N/NO3--N was 25:75,the content of nitrate and nitrite reached its minimum value.The nitrate nitrogen was good for accumulating the content of Vc and soluble polysaccharides.And the ammonium nitrogen was conducive to the accumulation of the content of soluble proteins and amino acids.At the NH4+-N/NO3--N ratio of 25:75,the polysaccharide contents and platycodin contents,Platycodon D content of Platycodon grandiflorum reached its maximum value.The total flavonoids contents was highest under CO(NH2)2 treatment.3.The activity of SOD,CAT,POD and the content of Pro were obviously increased by applying molybdenum under different nitrogen forms treatments.At the same time,the content of MDA was decreased significantly.The growth range of the yield,Pn and the total chlorophyll contents were highest by applying molybdenum under single nitrogen forms treatments.When NH4+-N/NO3--N was 25:75,the effects of applying molybdenum on increasing the activity of NR,nitrogen uptake,the nitrate content and decreasing nitrite content in Platycodon grandiflorum root were the most remarkable.And under this treatment,the polysaccharide contents,platycodin contents,Platycodon D content were also the highest.4.The content of photosynthetic pigments and Pn can be improved effectively with the treatments combined application of different nitrogen,phosphorus and potassium levels.The accumulation of dry matter increased constantly during the cultivation process of P.grandiflorum.The effect of nitrogen,phosphorus and potassium on the dry matter accumulation and the content of nitrate,free amino acids gave the sequence that was nitrogen>potassium>phosphorus.And the influence order on the content of nitrite,Vc and soluble proteins was nitrogen>phosphorus>potassium.5.The accumulation of N,P,K increased constantly during the cultivation process of P.grandiflorum.The Platycodon D contents decreased and then increased during the cultivation process of P.grandiflorum.The absorption of N,P,K contents in P.grandiflorum were 101.93,86.24and 158.10mg/plant within the whole period of cultivation.The N,P,K contents distributed in the aerial part of P.grandiflorum were more than the underground part at spring and summer.And it is the opposite at antumn.Within the whole period of cultivation,the absorptive capacity of is K highest,and the absorptive capacity of N is higher than that of P.And the most significant factor of the effects on the quality of P.Grandiflorum was Nitrogen fertilizer.When the N,P,K levels were 15,2and 6mmol·L-1,the content of Platycodon D was the highest.