Effect of PP333 on Cold Resistance in Korla Fragrant Pear

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.ResultCompared 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℃.ConclusionSpraying 1,500 mg/L paclobutrazol can effectively reduce the damage of shoots and improve the cold resistance of Korla fragrant pear.