Effect Of Abscisic Acid On Postharvest Physiology And Storage Of Chaoyang Dapingding Jujube(Ziziphus Jujuba Mill.)

Dapingding Jujube(Ziziphus jujuba Mill.), aliases Pingding Jujube, fruits are sweet with sour, crisp, delicious and nutritious. Dapingding Jujube is abundant in the western suburbs of Chaoyang County, Liaoning Province, and is an excellent jujube variety with strong resistance, high and stable yield. But Dapingding jujube is difficult to store, at room temperature, only keep crisp condition for a few days, and fruit easily dehydration shrinkage, softening. Once the flesh goes soft and drip loss, the fresh quality will be greatly reduced. Even at room temperature(20℃), Dapingding Jujube no climacteric peak after fruit harvest, does not meet the climacteric fruit characteristics, and therefore Dapingding Jujube is considered to be a non-climacteric fruit respiration. Abscisic acid(ABA) plays a series of significant physiology roles in higher plants including but not limited to promote bud and seed dormancy, accelerate foliage fall, induce stomatal closure, inhibit growth and enhance resistance. Recently, it has been revealed that ABA also has an important regulator role in the development and ripening of fruit. ABA is considered an important factor in the ripening of non-climacteric fruit. And the accumulation of endogenous ABA will cause fruit maturity and softening. This topic uses non-climacteric fruit Chaoyang Dapingding Jujube as materials at low temperature(0℃) storage conditions, to study the effect of ABA on the storage quality and physiological characteristics of postharvest jujube and possible regulatory mechanisms. To study the effects of exogenous ABA, Gibberellins(GA3), Ethylene and Fluridone, Nordihydroguaiaretic acid(NDGA) treatments on the endogenous ABA, GA3 biosynthesis and fruit storage quality and physiological characteristics of postharvest jujube. To provide the theoretical basis and positive reference for further research on ABA signaling regulation and postharvest storage of non-climacteric fruit Dapingding Jujube.The main results of this research topic are as follows.During low temperature(0℃) storage, ABA is an important plant hormone, resulting in the ripening and senescence of Dapingding Jujube. Applying exogenous ABA can very significantly(p<0.01) to promote Dapingding Jujube mature and aging, and induction of endogenous ABA content peak occurs earlier 5d, and the peak value of endogenous ABA content was significantly(p<0.01) higher than Fluridone, NDGA treatment groups. Exogenous ABA and Ethrel treatments could promote the accumulation of endogenous ABA of Dapingding Jujube, and the effects of exogenous ABA significantly higher than Ethrel. Exogenous GA3 can exert significantly(p<0.01) inhibit the endogenous ABA biosynthesis and improve the endogenous GA3 content of Dapingding Jujube. The antagonism of GA3 and ABA, making the ripening and senescence process slows of Dapingding Jujube. Treatments with ABA biosynthesis inhibitor Fluridone, NDGA, Dapingding Jujube could keep good storage quality, can maintain Dapingding Jujube lower endogenous ABA content during low temperature(0℃) storage.Through the determination of decay rate, weight loss, moisture migration, ascorbic acid content, titratable acidity, soluble solids content, sugar content and other nutritional ingredients and color, MDA, membrane permeability, alcohol content, soluble protein changes and other physiological indicators, compares the effects of different treatments on the storage jujubes. The experimental results showed that exogenous GA3, Fluridone, NDGA treatment have a good preservation effect. Compared with the control group, exogenous ABA treatment group, Ethrel treatment group, exogenous GA3, Fluridone, NDGA treatment(especially Fluridone, NDGA treatment) can effectively inhibit the jujube fruit ascorbic acid content decreased and water loss, keep jujube soluble solids content and titratable acid content, maintain sugar content to stability, delay the degradation of protein macromolecules, reduce jujube decay rate, delay fruit senescence. And exogenous GA3, Fluridone, NDGA treatment in addition to effectively suppress jujube fruit senescence and loss of nutrients, but also to varying degrees, to delay the decline of MDA content and increase flesh firmness of jujube, reduce the accumulation of alcohol content, maintain jujube flesh color to stability and the integrity of cell membrane, avoid flesh browning and softening and keep bright colors for a long time. ABA biosynthesis, accumulation and metabolic may regulate the loss of nutrients and physiological metabolic activity of Dapingding Jujube.Between textural properties and starch content, amylase activity, pectin content, PG activity of Dapingding Jujube has great relevance. Amylase and PG is the key enzymes involved in jujube fruit softening, amylase and PG activity peaks appear along with the beginning and increasing of jujube softening. And exogenous ABA, ethylene treatment can make jujube activities peak of these two enzymes in advance, however exogenous GA3, Fluridone, NDGA treatment can delay the onset of both peak activities. So amylase mainly in seven or eight mature jujube to finish ripening transition process has very high activity, influencing starch hydrolysis into soluble sugar and other substances, accompanying fruit ripening in immature jujube. However, PG activity in the maturity to the aging process is high, influencing jujube fruit pectin content, work in the late stage of fruit aging and softening.These results illustrate that ABA regulation of the maturity and senescence of Dapingding Jujube by influencing hormone changes, loss and degradation of nutrients and abnormal metabolic activity of cell physiology in fruit. Exogenous ABA, ethylene can enhance the regulatory capacity of ABA on fruit ripening, correspondingly, the antagonism of GA3 and ABA biosynthesis inhibitor Fluridone, NDGA can effectively suppress the regulation roles of ABA. This shows that ABA may be the upstream regulatory signals of ripening and senescence of non-climacteric fruit, resulting in the physiological metabolic disorders and storage quality decline of postharvest Dapingding Jujube.