采前赤霉素处理对李果实采后冷害的抑制及部分机理研究

Controlling chilling injury of plum with preharvest GA3 in postharvest and its partial mechanism

为探讨果实发育期喷施赤霉素(Gibberellin,GA3)对李果实采收时及冷藏期间冷害的抑制作用及机理,以‘红宝石’李为试材,在果实膨大期前1周、果实膨大期、果实膨大期后1周分别喷施1次100 mg/L GA3,研究GA3处理对果实冷藏期间冷害的抑制效果,及其对果实采收及冷藏期间细胞膜完整性、活性氧积累及抗氧化酶活性的影响。结果表明:采前GA3处理显著降低了李果实低温贮藏期间的冷害指数与褐变指数,贮藏第49 d时GA3处理果实的冷害指数和褐变指数分别较对照低60.61%和52.19%。GA3处理有效维持了果实冷藏期间细胞膜的完整性,抑制了丙二醛(MDA)的积累,显著降低了果实采收时及冷藏期间O2-.的产生和H2O2含量;还显著提高了果实贮藏期间的超氧化物歧化酶(SOD)和过氧化氢酶(CAT)活性,同时抑制了果实采收时和贮藏期间的过氧化物酶(POD)和多酚氧化酶(PPO)活性。可见,在果实发育期连续喷施3次100 mg/L GA3,可有效控制李果实的采后冷害,其良好的控制效果与维持果实细胞膜的完整性、减少活性氧的积累、提高果实抗氧化能力及抑制褐变相关酶的活性密切相关。

To study the effects of GA3 spraying during fruit development on the chilling injury and inhibition mechanism of plum fruit at harvesting and during cool storage. The plum trees （cv. ＇Ruby＇） were sprayed with 100 mg/L GA3 for three times, at a week before fruit expanding stage, fruit expanding stage and a week after fruit expanding stage. The effects of preharvest GA~ application on chilling injury of fruit were investigated during cool storage. We also determined the cell membrane integrity, reactive oxygen species（ROS） accumulation and antioxidant enzymes activity in treated fruit at harvest and during cool storage. The results indicated that GA3 preharvest application significantly decreased chilling index（CI） and brown index（BI） of fruit during storage, CI and BI of the treated fruit were 60.61% and 52.19% lower than the control after 49 days of storage. The preharvest GA3 treatment maintained the integrity of the cell membrane, reduced the accumulation of malondialdehyde（MDA） during storage. GA3 remarkably decreased the production of 02-and H202 content at harvest and during storage. Moreover, the treatment notably increased the activity of superoxide dismutase（SOD） and catalase（CAT） during storage and inhibited the activity of peroxidase（POD） and polyphenol oxidase（PPO）. It is suggested that preharvest 100 mg/L GA~ application for three times during fruit development significantly reduced chilling injury of plum fruit during cool storage. The controlling mechanism is closely related to maintain membrane integrity, to decrease the accumulation of ROS, to improve fruit antioxidant capacity and to inhibit browning related enzyme activity.