Abstract: [Objective] To explore effects of different concentrations of paclobutrazol on cold resistance of Korla fragrant pear and lay the foundation for the cultivation and regulation of the fruit.[Method] In the shoot rapid growth period (April 30th), different concentrations of PP333 were sprayed on the new shoots of Korla fragrant pear;The sleeping branches of 1a Korla fragrant pear were selected as test materials and subjected to artificial low temperature treatment.The cold resistance index was measured and the logistic curve equation was fitted to calculate the critical semi-lethal temperature (LT50).Finally, the effect of paclobutrazol on cold resistance of shoots was analyzed.[Result]Compared with CK, spraying 1,000 mg/L of paclobutrazol could effectively reduce the relative conductivity and malondialdehyde content in the shoots, slow down the damage of plant cell membrane under low temperature stress, and promote the content of proline and soluble in the shoot protein content, soluble sugar content, SOD activity and increased recovery germination rate.The semi-lethal temperature (LT50) was determined by Logistic inflection point and the semi-lethal temperature of 1,500 mg/L paclobutrazol was determined to be-28.80℃, while the semi-lethal temperature of CK was-25.21℃.[Conclusion]Spraying 1,500 mg/L paclobutrazol can effectively reduce the damage of shoots and improve the cold resistance of Korla fragrant pear.

摘要： [目的]研究不同浓度的多效唑对库尔勒香梨抗寒性的影响,为库尔勒香梨栽培提供理论基础.[方法]在新梢快速生长期(4月30日),对库尔勒香梨新梢喷施不同浓度的PP333,在休眠期,选取一年生枝条为试材,并进行人工低温处理.测定枝条中各抗寒生理指标,并拟合Logistic曲线方程,计算低温半致死温度(LT50),分析多效唑对枝条抗寒性的影响.[结果]与CK相比,喷施1 500 mg/L的多效唑可以有效减缓枝条中相对电导率和丙二醛的含量,减缓低温胁迫对植物细胞膜的破坏;同时促进枝条中游离脯氨酸含量、可溶性蛋白含量、可溶性糖含量SOD活性和提高恢复生长萌芽率.通过Logistic拐点确定半致死温度(LT50),1 500 mg/L多效唑处理的低温半致死温度为-28.80℃,而喷清水处理(对照 CK)的低温半致死温度为-25.21℃.[结论]喷施1 500 mg/L的PP333可有效减缓低温对枝条的伤害,提高库尔勒香梨枝条的抗寒性.