Study Of CaCl₂on Fruit Cracking Of Different Jujube Cultivars In Xinjiang

These different jujube cultivars (‘Jinlingyuanzao’,‘Hamidazao’,‘Huizao’,‘Junzao’, ect.)which produced in Xinjiang was used as test material in the experiment. The ten test materialjujube cultivars were immersed by different concentrations of CaCl2(0g/L,2.5g/L,25g/L) inseven stages of time(0h,12h,24h,36h,48h,60h,72h) in order to compare the change ofcracking fruit rate, fruit firmness, soluble solids, water potential, VC, water absorption and Ca,Mg, K content in fruit pupl and peel, differences of organizational structure in different jujubecultivars fruit was investigated. The result indicate: cracking rate of jujube fruit is linearupward in12h, cracking rate of jujube fruit is stable after60h.‘Zanhuangdazao’ had thehighest cracking rate, followed by ‘Junzao’, while ‘JinLingyuanzao’ has the lowest crackingrate among ten jujube cultivars, fruit cracking rate, water absorption rate，water potential andhardness had the significant difference separately among different treatments in the samecultivars. Both25and2.5g/LCaCl2can effectively reduce the jujube fruit cracking rate, andthe former was superior than the latter. The Ca content of fruit pulp and peel in the highestcrack resistance cultivar was higher than that in the lowest crack resistance. With increasingof CaCl2concentration, the Ca content was also increased. The K content of fruit pulp and peelin the highest crack resistance jujube was higher than that in the lowest crack resistance. Onthe contrary, the Mg content of fruit pulp and peel in the highest crack resistance jujube waslower than that in the lowest crack resistance.The content of Ca, K in fruit pulp and peel werenegative correlated with fruit cracking rate, the Mg content of fruit pulp and peel werepositive correlated with fruit cracking rate. The thickness of layer wax and cuticle in differentjujube cultivars had no significant differences in0g/L CaCl2dipped fruit0h,12h,36h,60h,but the thickness of layer wax ‘Jinlingyuanzao was thicker than ‘Junzao’, the thicknessepidermis of ‘Jinlingyuanzao’ was thicker than ‘Junzao’, The layer cell epidermis‘Jinlingyuanzao’ is more than ‘junzao’. When soaked fruit0h, cuticle cells, epidermis cellsof ‘Jinlingyuanzao’ and ‘Hamidazao’ arranged neat tight, and flesh cells arranged tightlywithout rules, cuticle cells of ‘Junzao’ arranged loose, intercellular had no gaps, epidermalcells arranged rules, but flesh cell of ‘Huizao’ had with cavity. When0g/L,2.5g/L,25g/LCaCl2dipped fruit12h,36h,60h,‘Jinlingyuanzao’ and ‘Hamidazao’ had no greatchanges, cuticle cells and epidermis cells arranged neat and tightly, pulp cells arranged loosely,cuticle of ‘Junzao’loosely arranged, larger gaps between cells, epidermal cells had differentsizes, arranged loosely without rules, pulp cavity of ‘Huizao’was larger. The conclusion show:‘Zanhuangdazao’,‘Junzao’ have the lowest crack resistances, while ‘Jinlingyuanzao’ and‘Dongzao’ have the highest crack resistance among ten cultivars. Compared with0g/L CaCl2,the2.5g/L CaCl2had the higher crack resistance, the25g/L CaCl2had the highest crackresistance among different treatments. Water absorption rate, water potential, Vc and soluble solids were positive correlated with the fruit cracking rate, the fruit cracking rate was negativecorrelated with hardness. Fruit soaked by CaCl2increased Ca content of jujube fruit pulp, peel,and impacted K, Mg content of four varieties of jujube. Cuticle layer of the highest crackresistance cultivars was thicker, cuticle cell arrange neat and rule, epidermal layer was thickerand cell was neat and rule. but cuticle layer of the lowest crack resistance cultivars wasthinner, and cuticle cell arrange disorderly, epidermal layer was thinner.