Effects Of Flat Stubble And Fertilization On Growth And Physiology Of Quercus Variabilis Container Seedlings

In this study,the container seedlings of Quercus variabilis were investigated to detect the relationship between the growth of the seedlings and the metabolism of active oxygen in the roots,and determine the effects of N,P,K exponential fertilization on the growth,root characteristics,physiological and biochemical characteristics and element absorption efficiency of Q.variabilis.The purpose is to provide effective theoretical basis and technical support for the cultivation of Q.variabilis container seedlings.The main results are as follows:（1）The root physiology of germinating seedlings and non-germinating seedlings of Quercus variabilis was studied by the method of flat stubble.It was found that the container seedlings of Q.variabilis began to germinate 14 days after flat stubble,and the activity of SOD in the roots of germinating seedlings and non-germinating seedlings decreased along experiment time.The activities of POD in the roots of the non-germinating seedlings increased firstly and then decreased,where that in the non-germinating seedlings increased significantly.The peak of CAT activity in the roots of non-germinated seedlings was later than that in germinated seedlings.The MDA content in the roots of germinated seedlings was significantly higher than that of non-germinated seedlings,and the soluble protein content in the roots of both treatments increased gradually.The results suggested that the membrane structure was destroyed gradually and the root system was prone to die due to the accumulation of oxygen free radicals and the lack of effective supplement of photosynthetic products.（2）The growth and root physiology of Q.variabilis container seedlings were studied by exponential fertilization method.The results showed that the plant height,ground diameter,root biomass,total root length,root surface area,root volume and specific root length of container seedlings increased first and then decreased with the increase of nitrogen（N）concentrations.Under N-300 treatment（300 mg / plant）,the values of each index were the largest.Compared with N-0 treatment,the activity of SOD,POD,CAT and the content of soluble protein were significantly increased,while the content of MDA was decreased by 24.2%.N,P and K contents in root system increased firstly and then decreased with the increase of N concentrations,which increased by 74.9%,48%,131% respectively under N-300 treatment.It suggested that N-300 was adoptable fertilization for Q.variabilis container seedlings.When the nitrogen fertilizer was more than 300 mg / plant,the growth of Q.variabilis would be suppressed and the seedlings would be poisoned.（3）The results showed that the plant height,ground diameter,root biomass,total root length,root surface area,root volume and specific root length of container seedlings increased first and then decreased with the increase of phosphorus（P）concentration.Under P-200 treatment（200 mg / plant）,the values of each index were the largest.Compared with P-0 treatment,the activity of SOD,POD,CAT and the content of soluble protein were significantly increased,while the content of MDA was decreased by 23.4%.N,P and K contents in root system increased firstly and then decreased with the increase of P concentrations.N,P,K contents in root system increased by 70.2%,77.3%,123% respectively under P-200 treatment.It suggested that P-200 was the best phosphorus fertilizer for Q.variabilis container seedlings.When the phosphorus fertilizer was more than 200 mg / plant,the growth of Q.variabilis would be suppressed and the seedlings would be poisoned.（4）The plant height,ground diameter,root biomass,total root length,root surface area,root volume and specific root length of container seedlings increased first and then decreased with the increase of potassium（K）concentration.Under K-200treatment（200 mg / plant）,the values of each index were the largest.Compared with K-0 treatment,the activity of SOD,POD,CAT and the content of soluble protein were significantly increased,while the content of MDA was decreased by 31.9%.N,P and K contents in root system increased firstly and then decreased with the increase of K concentrations.N,P,K contents in root system increased by 70.2%,48.5% and89.3% under K-200 treatment,respectively.It suggested that K-200 was the best potassium fertilizer for Q.variabilis container seedlings.When the potassium fertilizer was more than 200 mg / plant,the growth of Q.variabilis would be suppressed and the seedlings would be poisoned.