Study On The Relationship Between Jujube Peel Structure,Cell Wall Metabolic Enzyme Activity And Resistance To Cracking

In this study,the anti-cracking ash jujube and the fissile jujube were used as materials to observe the surface and anatomical structure of jujube peel and the activity of enzymes in the cell wall of the pericarp by using paraffin section and scanning electron microscopy.The mechanism of jujube fruit cracking provides a theoretical basis for further understanding the anti-crack mechanism of jujube fruit and scientific control of cracking fruit.The main findings are as follows:(1)It was observed by scanning electron microscopy that no cracks in the surface wax layer were found in the early stage of fruit development,and cracks appeared in the semi-red stage,and the surface pores slowly opened from the before white ripening stage to the white ripening stage to fruit development.There was no significant change in the size of the stomata in the later stage;the cracks in the waxy layer on the surface of the susceptible jujube varieties gradually became smaller during the development process,and the stomata on the surface of the fruit slowly opened during the development process,and the stomata were blocked at the late stage of development.The experimental results show that the micro-cracks and stomata clogging on the surface of jujube fruit are the factors causing macro-cracking of the fruit.The larger the micro-crack on the surface of the fruit,the more susceptible the fruit is to crack,and the more severe the stomata blockage,the more susceptible the fruit is to crack.(2)After the paraffin section was observed,the thickness of the waxy layer of the anti-cracked jujube variety was significantly greater than that of other periods in the white ripening stage.The thickness of the stratum corneum gradually thickened during the development process,and the thickness of the epidermis layer slowly developed during the development process.Thinning;the thickness of the waxy layer of the susceptible jujube variety is gradually thickened during the development process,and the thickness of the stratum corneum is gradually thickening during the development process,and there is no significant change in the late development stage.The thickness of the epidermal layer is not significant in the early development stage.Change,slowly thinning later in development.The experimental results show that the thickness of the wax layer,the thickness of the stratum corneum and the thickness of the epidermis are also the factors that cause the fruit to crack.The thicker the thickness of the wax layer and the thickness of the epidermis,the more difficult the fruit is to crack,and the thinner the stratum corneum,the more difficult the fruit is to crack.(3)The results showed that SOD activity,POD activity,PPO activity,CAT activity,pectinase activity and cellulase activity were all related to fruit cracking.Among them,SOD activity,POD activity,PPO activity and CAT activity in different parts.There are differences in fruit development.The higher the activity of SOD activity in the pre-developmental stage of stems and shoulders,the more susceptible the fruit is to crack,and the higher the activity of the stems to the late stage of development,the more difficult the fruit is to crack;the POD activity is in the stems,fruit tops,shoulders,shoulders and shoulders.The pre-developmental stage of the four parts was consistent with the activity of SOD,and the higher the activity,the more likely to be cracked.There was no significant relationship between POD activity and fruit cracking at the late stage of development;the higher the activity of PPO activity in the pre-developmental stage,the more likely to crack,and the later stage of development.The higher the activity,the more difficult it is to crack.Only the higher the PPO activity in the late stage of fruit development,the more difficult it is to crack.The PPO activity in the stalk and the fruity shoulder has no significant relationship with the cracked fruit.The higher the activity of CAT activity in the early stage of fruit development,the easier it is.There is no significant relationship between cracking and fruit cracking at the late stage of development;the higher the pectinase activity and cellulase activity,the less likely to crack.