The Forming Mechanism And Prevention Of Fruit Spot On Zhongqiusucui Jujube

Zhongqiusucui jujube is the main variety of Hunan jujube,and its development area is about 10 million mu.Fruit spot is an important fruit disease of Zhongqiusucui jujube.To explore the relationship between the formation of fruit spots and the external environment and provide reference for the control of fruit spots,the development time,location,shape,color,average size,morbidity of jujube fruit and the structure of epidermis were observed and measured by environmental and meteorological investigation combined with stereoscopic observation,electron microscopy and paraffin section.The results were as follows.(1)Zhongqiusucui jujube fruit spot is a physiological disease,and can be divided into two types:protruding spots and cracking spots.Protruding spots occurred in young fruit,formed by stomatal development.The growth rate of jujube fruit was fast,and epidermal infection could not make the whole fruit to become bad or fall off,only forming a fruit point similar to scars.Protruding fruit spots only affect the appearance of fruit quality,could not reduce the fruit yield and affect the shape of the fruit,and do not reduce the taste,so the protruding spots could not be as the prevention and control objects of orchards.Cracking spots occurred in the white ripening of jujube fruit,due to the strong speculation of intense external conditions.There was no significant correlation between the rupture type and the distribution of the stomata.The formation of the spots was random,mainly due to the formation of the epidermal cells and the rupture of the stratum corneum.The appearance of fruit spots such as rusty rough skin thickening,with some thick spots of pulp make the growth of jujube fruit not easy to mature.After ripe,the fruit spots were black red(normal fruit is bright red),fruit skin slightly shrinkage,and taste bad,seriously affecting the fruit of the commodity value.The protruding spots occurred in the high temperature and humidity environment,developed and formed form stomata,and there were different bacterial colony in different spots.The incidence rate of protruding fruit spots was 31.23%,and the relative area of the diseased fruit spots was small,which has no significant effect on the fruit weight and size of the jujube fruit,so the protruding spots only affected the appearance of the fruit,usually did not make great effect on the production.The cracking spots occurred in the high temperature and hard light environment,developed and formed form both stomata and other area.The average flesh thickness of the spotted fruit was 1.30 mm less than that of the non-pollinated fruit,and the average diameter of the fruit was 2.92 mm less than that of the non-polluted fruit.The spotted fruit weight was 2.35g less than that of the untreated fruit.All of them reached the significant level,which had important influence on fruit yield and quality.(2)Different bagging treatment can improve the appearance of Zhongqiusucui jujube quality.Tin foil wrapping treatment could prevent the occurrence of fruit,and at the same time could significantly reduce the occurrence of physiological fruit drop,but it led to the reduction of the inherent quality of fruit.This bagging method has a certain limit in the production.The non-woven bagging treatment not only improved the appearance of quality,but also had not significant on impact the inherent quality of the fruit.(3)The formation of fruit spots is associated with the activity of peroxidase(POD),polyphenol oxidase(PPO)and alanine ammonia lyase(PAL).Non-woven bag treatment,tin foil treatment,and kraft paper bag treatment could effectively inhibit the activity of peroxidase(POD),polyphenol oxidase(PPO)and alanine ammonia lyase(PAL).