| This paper studied the effect of different exogenous microbial agents on the soil polluted by quinclorac c by combing the pot experiment and field experiment including the tobacco's physiological indices(reactive oxygen,antioxidant rate,protective enzyme,photosynthetic pigments,chlorophyll fluorescence parameters,NR activity,Inv activity etc),tobacco-planting soil's eco-physiological indices(rhizosphere and non-rhizosphere soil microorganism quantity&soil enzyme),tobacco's soluble protein electrophoretogram,SOD isozyme electrophoretogram and cytoderm expansin electrophoretogram,the anatomical structure of tobacco's different positions(stem tip,parietal lobe,middle part,root tip),field tobacco's economical character,yield and output as well as tobacco's chemical component repair aiming to explore the repair effect of exogenous microbial agents on the tobacco-planting soil and tobacco damaged by quinclorac c and then screen out the best exogenous microbial agent and its application method.The experimental results are as follows:1.The repair effect of exogenous microbial agent on tobacco's physiological property under the quinclorac stressWith the time extesion,the Pro,soluble sugar,soluble protein in normal tobacco incrased gradually and the K+ content firstly increased then decreased to some extent,while the relative electrolytic leakage maintained within a relatively low level,but after damaged by quinclorac,the Pro,soluble sugar and relative electrolytic leakage increased with the soluble protein and K+ content decreased obviously.After the exogenous microbial agent repair,the osmoregulation substance content in tobacco increased with osmotic adjustment ability growth and relative electrolytic leakage decline,which strengthened the resistance of tobacco under the quinclorac adversity stress.The biological bacterial fertilizer and microbial agent share the best combined treatment effect among exogenous microbial agents.Damaged by quinclorac,the protective enzyme SOD,CAT and APX activity level in tobacco were relatively low with not high reactive oxygen clearance ability and decreasing O-2·clearance rate,·OH clearance rate and oxidation resistance,which increased the O-2·,·OH content in tobacco and caused the tobacco's membranous oxidative product MDA content growth.The tobacco's antioxidant enzyme SOD,CAT and POD activity increased obviously with different exogenous microbial agents,which enabled to eliminate the reactive oxygen in tobacco effectively and enhacne the O-2·,·OH clearance rate and decrease the O-2·,·OH contents so as to decline tobacco's membranous oxidation,alleviate the damage on tobacco and promote the normal growth of damaged tobacco.Meanwhile,it was found that the tobacco root system is more sensitive and can be easily injured than leaf under the quinclorac stress.The exogenous microbial agent owns certain repair effect on autioxidant enzyme activity and reactive oxygen content as well as clearance rate of tobacco damaged by quinclorac,of which T4 and T2 share relatively well repair effect and then come to T3.The tobacco's photo synthetic pigments content decreased after damaged by quinclorac and the Fv/Fm,?PS?,dP also decreased by reaching an obvious level with distinctive increase on NPQ,which decreased plant's light use efficiency with large loss on photosynthetic energy.The tobacco's chlorophyll a,chlorophyll b,total chlorophyll content,Fv/Fm value,?PS? value and dP value increased after implanted with exogenous microbial agent compared with that of damaged control,which then increased the photosynthesis intensity,enhanced the light energy transformation and electron transfer efficiency and declined the NPQ value after repair treatment so as to decrease light energy dissipation and improve photosynthetic efficiency.On the whole,the exogenous microbial agent's repair effect on photo synthetic pigments and chlorophyll fluorescence parameters of damaged tobacco showed as T0>T4>T2>T3>T1,of which T4 owns the best repair effect.The tobacco's NR,Inv,GST and ALS activity decreased and the GSH content,LAAOase activity and Cx activity increased after damaged by quinclorac.The tobacco's NR,Inv,GST and ALS activity increased,while the GSH content,IAAOase activity and Cx activity decreased after implanting the exogenous microbial agant.On th whole,the various enzymatic activity in root system was much lower than that in leaf;the repair effect of various treatments on dameged tobaccos showed as T0>T4>T2>T3>T1.2.The repair of exogenous microbial agent on tobacco-planting soil's physio-ecological characteristics under quinclorac stressCompared with normal soil,the bacterial,fungus and actinomycetes quantity in tobacco-planting soil decreased to some extent under the damage of quinclorac.The number of microflora recovered gradually after repairing the soil by implanting different exogenous microbial agents,of which the treatment T4 owns the best repair effect;the catalase activity,sucrase activity and urease activity decreased under the damage of quinclorac compared with that in normal soil,but all of them enhanced after repairing by implanting exogenous microbial agents.The rhizosphere soil owned higher microbial quantity and enzyme activity than that of non-rhizosphere soil.The three repair effects of tobacco-planting soil's physio-ecological characteristics under the damage of quinclorac c showed as T4>T2>T3.3.The repair of exogenous microbial agent on tobacco's electrophoretogram under quinclorac stressThe soluble protein SDS-PAGE electrophoretogram analysis indicated that the protein bands in tobacco disappeared and the zymogram bands of SOD isozyme got restricted with overly expressed cytoderm expansins under quinclorac stress.However,the disappeared soluble protein bands recovered expression and the SOD isozyme along with cytoderm expansins gotten repaired preferably after implanting exogenous microbial agent.Compared with various repair treatments,treatment T4 owns the best repair effect on soluble protein,SOD,cytoderm expansin eletrophoretogram,then comes to T2,while T3 has the worst effect.4.The repair of exogenous microbial agent on tobacco's anatomical structure under quinclorac stressAccording to the paraffin section and microscope observation,the organizational structure of tobacco among various treatments shared obvious difference,which was specified as follows.The normal control owned the maximum diameter and vertical section of stem tip,then came to repair treatment and the damaged stem tip finally;in terms of differentiated degree,the damaged stem tip was fastest,then came to repair treatment and normal control finally;the damaged tobacco owned the thickest epidermis of top and middle part as well as the palisade tissue and spongy parenchyma,then came to repair tobacco and normal tobacco finally;the thickness of epicuticle,hypodermis,palisade tissue and spongy parenchyma of middle part was much smaller than that of normal tobacco.The results showed that the quinclorac had severe damage on tobacco stem tip and top part anatomical structure and lighter damage on anatomical structure of middle part and root system.The damaged symptom of anatomical structure of damaged tobacco got alleviated after adding exogenous microbial agent into soil,which indicated that the exogenous microbial agents has certain degradation on the residual quinclorac in soil.5.The repair of exogenous microbial agent on field soil's physio-ecological characteristics and tobacco's enzyme activity with residual quincloracCompared with normal soil,the bacterial,fungus and actinomycetes in rhizosphere soil of tobacco field as well as the catalase activity,sucrase activity and urease activity decreased under the damage of quinclorac.However,the number of microflora and various enzyme activity increased after exogenous microbial agent repair with different applicatio nmethods.On the whole,the combined last-year and next-year application of exogenous microbial agent will produce the best effect and the past-year application,next-year application owns the worst repair effect.The filed damaged tobacco's GSH content,Inv,GST and ALS activity decreased obviously compared with that of normal tobacco,while various repair effect showed as A>E>C>D>B after repairing by exogenous microbial agent with different application methods.6.The repair of exogenous microbial agent on filed tobacco's economical character&yield and output with residual quincloracThe tobacco's economical character with different treatments during topping time showed distinctive difference.The plant height and stem girth of damaged tobacco decreased 33.9%and 16.9%respectively with 0 normal leaf compared with that of normal tobacco;the plant height and stem girth of C,D,E increased 24.8%,30.5%,55.7%and 18.1%,12.5%and 27.3%after repairing by exogenous microbial agents with different application methods with the normal leaf recovering to four,four and thirteen pieces compared with that of damaged control.The E treatment shares the best effect among various repair treatments.The flue-cured tobacco yield,average price,acre yield and the proportion of middle and first tobacco of E treatment are higher than that of damaged control but lower than that of normal control.The yield,average price,acre yield and the proportion of middle and first tobacco of E treatment increased 80.9%,18.1%,121.3%and 173.8%compared with that of damaged control.The results indicated that application method of last-year broadcast and next-year hole fertilization will have obvious effect on repairing the damage of quinclorac on tobacco production.7.The repair of exogenous microbial agent on tobacco's main chemical component with residual quincloracCompared with normal tobacco,the main chemical component of damaged tobacco including K+ content,total sugar and reducing sugar content are lower than that of normal tobacco,while the nicotine and total nitrogen are higher than that of normal tobacco with inconsistent medical components such as total sugar/reducing sugar content,nitrogen/alkali etc;the K+,total sugar and reducing sugar content increased,but the nicotine and total nitrogen content decreased with coordinated medical component after exogenous microbial agent repair.Besides,various indices get recovered to some extent.The total sugar and total nitrogen share the best repair effect,while the repair effect of different medical components of various treatments exist certain difference.The repair effect of total sugar,K+and total sugar/nicotine showed as A>E>C>D>B;the total nitrogen and nicotine showed as B>D>C>E>A;the reducing sugar contents showed as A>D>E>C>B;the reducing sugar content/total sugar presented as D>A>E>C=B;the nitrogen/alkali showed as A>D>E=C>B;the treatment E owns the best repair effect by comprehensive evaluation. |
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