The Research Of Korla Fragrant Pear On Cold Physiological Changes Of Different Exogenous Hormone Treatment

This experiment taked Xingjiang Bazhou Korla pears as the research material. In the growing period(May to July) and before the defoliation period(October), Fragrant pear leaves sprayed different times with different concentrations of exogenous abscisic acid(ABA: 50, 70, 90 mg/L), gibberellic acid(GA3: 50, 75, 100 mg/L) and indole-3-acetic acid(IAA: 80, 100, 120 mg/L). To study the changes of exogenous hormones content in Korla Pears leaves with different concentrations of endogenous hormone under the two periods; and the physiological cold resistance characteristics of one year old branches, such as membrane permeability, content of MDA, proline, soluble protein, soluble sugar and starch contents, etc., were measured at low temperature stress. A comprehensive evaluation on cold resistance was given based on fuzzy membership function analysis. Then explore the cold effect of spraying different exogenous hormones and concluded the best concentration and treatment period. Test results are as follows:(1) Fragrant pear leaves were sprayed different times with different concentrations of ABA, GA3, IAA in the growing periodWith the concentration and times of exogenous ABA spraying increased, the average membership decreased. Endogenous ABA content of Leaves increased, while the endogenous GA3 and IAA content decreased, resulting in a significant increasing in endogenous ABA/GA3 ratio. High concentrations of GA3(100 mg/L) helped to improve cold hardiness, but cold hardiness reduced with the times of spraying increased, the average membership was higher with low concentrations of IAA(80 mg/L) treatment. But with the increasing in the number of spraying, the concentration of 100 mg/L IAA boosting of cold hardiness. Endogenous ABA content decreased in leaves with increasing the concentration and frequency of treatment of exogenous GA3 and IAA; while the endogenous GA3 and IAA content increased, making the ABA/GA3 ratio decreased.(2) Fragrant pear leaves were sprayed different concentrations of ABA, GA3, IAA before the defoliation periodTreatment of exogenous ABA could effectively alleviate the adverse effects of low temperatures on the physiology. In this treatment, the synthesis of GA3 was inhibited, then the endogenous ABA content, ABA/GA3 and ABA/(GA3+ IAA) ratio were all Increased. To improve cold hardiness, the best ABA concentration was 70 mg/L. Followed by 100 mg/L IAA treated, because extremely high concentration could reduced the ABA/GA3 and ABA/(GA3 + IAA) ratio. With the average membership analysis, ranked last was 50 mg/L GA3 treatment.Comprehensive analysis, comparing the impact of exogenous hormone treatment of Korla Pear cold hardiness in growing period and before the defoliation period, the latter was better. And the physiological indicators and endogenous hormone were significant difference. Consequently, the best exogenous ABA concentration is 70 mg/L and the IAA concentration is 100 mg/L and the GA3 concentration is 75 mg/L.