Effects Of Two Restorer Mixtures On The Growth,physiology And Soil Phenolic Acids Of Replanted Zanthoxylum Bungeanum

Chinese red pepper（Zanthoxylum bungeanum）as a deciduous small tree or shrub of the genus Zanthoxylum（Rutaceae）,with early income,wide use,high value and adaptability,is the main economic tree,drought-resistant trees and soil conservation species in some parts of China.In recent years,due to the rapid development of agricultural and forestry industry intensification and commercialization,also makes the phenomenon of monoculture planting of Chinese red pepper increasingly widespread,resulting in soil nutrient imbalance,plant resistance to decline,soil chemosensitive self-toxic substances accumulation,also make soil-borne diseases occur seriously,Chinese red pepper seedlings will appear yield,quality decline,low survival rate and a series of crop problems,which seriously restrict the Chinese red pepper industry development.Therefore,how to effectively mitigate cropping barriers has become one of the urgent industrial problems to be solved.Hence,in this study,bioorganic fertilizer and microbial fertilizer with different volume ratios were used as remediation agents,and eight treatments were set up:T0（no fertilizer control group）,T1（microbial fertilizer）,T2（bioorganic fertilizer）,T3(V_{microbial fertilizer}∶V_{bioorganic fertilizer}=1∶2),T4（Vmicrobial fertilizer∶Vbioorganic fertilizer=1∶4）,T5（Vmicrobial fertilizer∶Vbioorganic fertilizer=1∶1）,T6（Vmicrobial fertilizer∶Vbio-organic fertilizer=2∶1）,T7（Vmicrobial fertilizer∶Vbio-organic fertilizer=4∶1）;simulated continuous cropping in the field to investigated its effects on the growth,physiology and soil phenolic acids of replanted Chinese red pepper seedlings to reveal the growth-promoting mechanism of the two mixed applications on replanted Chinese red pepper,aiming to provide reference for the fertilization management of old Chinese red pepper plantations and alleviate replanting obstacles.The main results were as follows:（1）After the treatment of both restorers,the height,stem thickness and biomass of the replanted Chinese red pepper seedlings increased to different degrees compared with the control T0,among which,the stem thickness and height of T4 and T5 increased the most significantly compared with the control,respectively,while the biomass increased the most significantly in the T6 treatment,indicating that the higher proportion of microbial fertilizer in the mixture of bioorganic fertilizer and microbial fertilizer could promote the elongation growth and biomass of Chinese red pepper.（2）After the mixtures treatment with both restorers,net photosynthetic rate（P_n）,stomatal conductance（G_s）,transpiration rate（T_r）,potential photochemical efficiency（F_v/F_m）,photochemical burst coefficient（q P）and actual photochemical efficiency（ΦPSII）of replanted Chinese red pepper seedings increased significantly compared with the control T0,and intercellular CO₂concentration（C_i）and non-photochemical burst coefficient（NPQ）decreased significantly,with T6 The plant growth and photosynthesis were promoted most significantly under T6 treatment,which effectively improved the light energy utilization of photosynthetic system PSⅡ,greatly increased seedling productivity,and accelerated the conversion of inorganic matter and organic matter accumulation.（3）After the mixtures treatment with both restorers,catalase（CAT）,superoxide gas dismutase（SOD）,peroxidase（POD）,and nitrate reductase（NR）activities in replanted Chinese red pepper seedlings tended to increase to different degrees compared with the control T0;soluble sugar and soluble protein contents also increased;malondialdehyde（MDA）content significantly decreased;chlorophyll a and b contents and total chlorophyll also increased to different degrees.Overall,the plants under T6 treatment had a high metabolic capacity and good uptake of fertilizer.（4）The application of the two remediation agents effectively reduced the content of gallic acid,caffeic acid and p-hydroxybenzoic acid,while the content of ferulic acid showed an increasing trend,but the total content of the four phenolic acids was reduced to different degrees compared with the control T0,with the most obvious reduction in T4,and the effect of mixed application was significantly higher than that of single application,which significantly reduced the chemosensitive substances in the inter-root soil.Among them,ferulic acid and caffeic acid had a larger base in the soil and were susceptible to environmental conditions,while gallic acid and p-hydroxybenzoic acid were relatively stable in the soil.（5）The correlation analysis showed that the content of caffeic acid in the soil affected the accumulation of biomass in the underground part of Chinese red pepper seedlings and was detrimental to the root development of seedlings;the content of gallic acid had a significant effect on the SOD,CAT,chlorophyll content and nitrate reductase activity of Chinese red pepper seedling leaves,which could significantly inhibit their activities,among which,the content of chlorophyll b was most significantly inhibited.Meanwhile,caffeic acid also had the same effect on POD activity and chlorophyll b content of seedling leaves.（6）The results of principal component analysis showed that the growth-promoting effects of different treatments on Chinese red pepper seedlings were in the following order:T6>T7>T5>T4>T2>T3>T1>T0.It can be seen that the restoration effect of microbial fertilizer and bio-organic fertilizer mixed pair of replantation barries of Chinese red pepper was higher than that of single application,and the interaction between them was better.Among them,a 2:1 volume ratio of the two had the best positive effect on replanted Chinese red pepper seedlings.Both improved the soil fertility level by reducing the content of soil phenolic acids in order to promote seedling physiological metabolism and increase seedling productivity,thus alleviating Chinese red pepper replanting problems.