Inhibition Of Ozone On Black Spot Disease Of Apricot Fruit

Apricot(Prunus armeniaca L.)is one of Xinjiang’s characteristic fruits.It is a breath-changing fruit,which is extremely rotten after harvest.Black spot disease caused by Alternaria alternata is the main postharvest disease of apricot fruits.Currently,chemical fungicides are mainly used to control post-harvest diseases of apricot fruit,but chemical fungicides are often used in excessive doses,leading to problems such as drug residues,environmental pollution and resistance to pathogenic bacteria.Therefore,a safe,green and effective apricot fruit storage method is needed to control postharvest diseases of apricot fruits.In this article,Xinjiang "Samaiti" apricots were used as test materials,and 100 mg/m3、200 mg/m3 and 300 mg/m3 ozone were used to fumigation apricot fruits,and damage was inoculated with A.alternata.The effects of ozone treatment on postharvest storage quality,active oxygen metabolism and phenylpropane metabolism of apricot fruits were studied,and the inhibitory effects of ozone fumigation treatment on black spot disease of apricot fruits were investigated.The main findings are as follows:(1)The results showed that ozone treatment had a certain inhibitory effect on the incidence of inoculation and the diameter of the lesions.But compared with 100 mg/m3 and 300 mg/m3,the 200 mg/m3 ozone treatment group had the best effect on inhibiting the expansion of apricot fruit lesion diameter and reducing the natural incidence and injury inoculation incidence of apricot fruits.200 mg/m3 ozone treatment group was more effective in inhibiting the increase in browning index,respiratory intensity and cell membrane permeability of post-harvest apricot fruit,slowing the solubility,the decrease of solid content,titratable acid content,ascorbic acid content and chlorophyll content,and can better maintain the firmness and color of apricot fruits.This indicated that 200 mg/m3 ozone treatment can effectively inhibit the expansion of apricot fruit lesion diameter and reduce the natural incidence and damage inoculation incidence of apricot fruit,and better maintain the post-harvest quality of apricot fruit.(2)200 mg/m3 ozone treatment can effectively inhibit the increase of superoxide anion(O2-·)production rate and MDA content of apricot fruits,and significantly increase the activities of antioxidant enzymes APX,SOD,POD and CAT and the content of soluble protein.This indicates that the increase of postharvest disease resistance of ozone treatment is closely related to the regulation of active oxygen metabolism.(3)200 mg/m3 ozone treatment can effectively increase the PAL,C4H,4CL,GLU and CHI activities of apricot frui,and maintain the accumulation of total phenols and flavonoids.That showed that ozone can enhance the disease resistance of apricot fruits by regulating the enzyme activities related to phenylpropane metabolism in apricot fruits.