Study On Inhibiting Decompose Of Pomegranate During Storage And Isolate And Indentify The Pathogenic Fungus

In this paper,JingPiTian pomegranate, as is the main species in LinTong county ShaanXi province, is used to research inhibiting decompose of pomegranate during the storage.In this experiment, pomegranate is treated by spraying with mildothane(for short JiaTuo),YiBao,PuDeJin pre-harvest and is treated by dipping in JiaTuo solution,fumigation of self-confect SO₂ controlled release formulation and Dimei aerosol post-harvest,and then obtains the best method base on the compare on effect of pomegranate antisepsis and storage quality of 6 factors 18 levels samples. In order to less the application amount of chemical preparations,the antisepsis effect of chitosan coating,water extract of pomegranate rind,water extract of clove and rhubarb is researched.In this paper, active mechanism of all treatments and the physiological change of pomegranate are discussed and revealed through the analysis and compare of respiration index,phenols content,ethanol content,rot index,rate of good fruit and the activity of PPO,POD,PAL and CAT.　At the same time, pathogenic fungus which makes Pomegranate rotting is isolated and identified, the infestation cycle,disciplinarian of pathogeny and infestation route of pathogenic fungus are investigated.The author concludes integrative technical measure to control the rot disease of pomegranate. The results showed that, using 2000 times JiaTuo diluent sprays pre-harvest has the best effect in all treatments ; marinating Pomegranate in 1500 times JiaTuo diluent post-harvest has the best effect in all treatments. The rot index of the two treaments is not remarkable difference. Because the time of first infestation and high peak infestation are from florescence to before setting pag, if spraying pre-harvest, the time of treatment should be from florescence to before setting bag. There have some remarkable effects of marinating Pomegranate in 1500 times JiaTuo diluent:reducing the rate of respiration during storage; restraining remarkably the degression of phenols contents; activating rapidly the activation of protective enzyme system POD(it's activation is 2.5 times to that of comparison after 15 days storage,forthemore the high level activation maintains longer time) ; decreasing the accumulation of ethanol of fruit; restraining the activation of PPO,CAT and PAL.Accordingly,it restrains effectively the oxidation course in pomegranate fruit, protects fruit cell organization structure,maintains all kinds of physiology metabolism normally, delays the consenescence of fruit, improves the disease resistance ability of fruit. Both the effects of rot index and good fruit rate of Pomegranate which treated by using JiaTuo alone is better than that of JiaTuo +chitosan coating,JiaTuo + water extract of pomegranate rind,JiaTuo + water extract of clove and rhubarb.JiaTuo +chitosan coating treatment can restrain remarkably the rate of respiration, and can increase the contents of ethanol, although the startup speed of POD activation is same as the that of blank control, the maintain time of activation is longer. The activation of PPO and CAT also show various degrees of inhibition, the activation level of PLA which induced by pathogen is low.The main reason is the thickness of JiaTuo +chitosan coating is not fitful,It makes fruit do anaerobic respiration,and then ethanol content increases, fruit cell structure and function are damaged by high level ethanol , cell structure and function can not be recovered,so cell decreases the disease resistance ability and increases death.Comparing with every biochemical and physiological index of fruit treated by JiaTuo + water extract of pomegranate rind,JiaTuo + water extract of clove and rhubarb, blank control and alone JiaTuo control, it shows that both respiratory index ,ethanol content, phenols content and the activation of PPO,PAL and CAT lies in cross that of blank control and alone JiaTuo control.It reveals that the two treatment (JiaTuo + water extract of pomegranate rind,JiaTuo + water extract of clove and rhubarb)have some effects to restrain pathogen , protect organization and delay consenescence on pomegranate fruit during storage. The peel and juice of pomegranate are determined at the end of storage.The results is 0.40798mg/kg and 0.03782mg/kg, shows that the residue is lower than national standard and is safe for eating. Isolation and identify the pathogen of pomegranate shows that it is Botryosphaeria dothidea.　There are two kinds rot symptom which aroused by Botryosphaeria dothidea depend on atmosphere humidity: the first is pericarp shows waterlogged brown clot at the beginning of infestation, then pericarp becomes black brown and have some particulates which is difficult to scrape down, fruitage becomes spongy rot and the seed is abnormity;the second is pericarp shows brown sunken dry area spot and rot speed is slowly than spongy rot. Botryosphaeria dothidea lives through the winter with the form of perithecium and bourgeons in warm wet springtime.It spreads through rainwater, air current and insect, and can enter and infest bud, young fruit or fruit from calyx lenticel injured scarfskin and hypanthium, fastigium of pathogeny is from May to July, Botryosphaeria dothidea lives through the winter inside of dry fruit and rotten tree bark. In this thesis, for the first time identify the pathogen of pomegranate with the gene method,and know that it is Botryosphaeria dothidea.First research systematacially the decompose mechanism of pomegranate, and reveal that JiaTuo 2000 times diluent spraying or marinating pomegranate in 1500 times can inhibiting pomegranate decay. Forthmore,the author discuss the inhibition mechanism of JiaTuo.