Effects Of Ratio Of N?P And K Fertilizer On Physiological And Release Negative Ions Concentration Of Asparagus Setaceus

The research mainly explores the effects of NPK fertilization on Asparagus setaceus and its release of negative ions concentration to optimize the combination of NPK which can improve the physiological resistant tolerance of asparagus and its release of NAI concentration and provide scientific fertilization theory for the plant selected to use in highly efficient,environmentally protective,energy-conservative "plant sources of negative ion generator" developed by our lab.We mainly determined chlorophyll content,soluble protein content,activity of MDA,activity of SOD,activity of CAT,activity of POD and NAI concentration upon the pulsed electrical field stimulation under the condition of different N,P and K concentration through L16(45)orthogonal design with 3 factor(N,P and K)and 4 levels(N1=0.08 g/L,N2=0.13 g/L,N3=0.18 g/L and N4=0.23 g/L;P1=0.01 g/L,P2=0.04 g/L,P3=0.07 g/L and P4=0.10 g/L;K1=0.02 g/L,K2=0.06 g/L,K3=0.10 g/L and K4=0.14 g/L).Main results were as follows:1.The NPK fertilizer has significant effect on asparagus physiological indexes during this experiment.The 16 combinations can increase the chlorophyll content and soluble protein content,therefore,improve its ability of photosynthesis and osmotic regulation,protect the cell membrane from lipid peroxidation effectively and maintain the stability of cell membrane system at the maximum;Over time(NPK fertilization after 0,21,42 and 63 days),the activity of SOD and CAT of the antioxidant enzyme system in asparagus increased,which leads to decrease of active oxygen and free radicals and increases its stress tolerance and delay the aging process.However,the activity of POD varies over time,which did not follow the trend of gradual increase after 0,21,42 and 63 days of NPK fertilization.The reasons for this phenomenon might be include:(1)the POD activity which was influenced by environmental factors sensitively show the irregularly complex variations because of high temperature in summer when the test was carried out;(2)the POD activity did not respond regularly to nutrition inbalance that was not obvious under NPK fertilization over time.2.The optimal combination of NPK on asparagus that show efficient generation of negative ions concentration upon the pulse electrical stimulation is A1B4C4,namely,0.08 g/L N,0.10 g/L P2O5 and 0.14 g/L K2O,the N fertilizer is the main factor influencing generation of negative air ions in asparagus.when the N level is A1,that is 0.08 g/L,the concentration of negative ions generated by asparagus under the pulse electrical stimulation is highest.The capacity of release of negative ions under the pulse electrical stimulation drops with the rise of N concentration in the range of fertilization of this study.the extent of influence of N,P and K on release of negative ions in asparagus under the pulse electrical stimulation during the experiment is N>K>P.3.We can conclude that the N,P4K4,namely,0.08 g/L N,0.10g/L P2O5,and 0.14 g/L K2O,is the optimal combination which can improve the physiological resistance of asparagus and its generation of NAI concentration through synthesizing the effects of NPK fertilization on the physiology of asparagus and its release of negative ions during the experiment.