Abstract: In order to improve the storage and transportation resistance of cut chrysanthemum，fresh cut flowers of Youxiang were soaked in distilled water，basic vase solution（30 g/kg sucrose+250 mg/L 8‑hydroxyquinoline+200 mg/L citric acid），melatonin solution（20 μmol/L） and basic+melatonin compound solution（20 μmol/L melatonin+basic vase solution） to explore the preservation effect of melatonin on cut chrysanthemum. Based on the previous results of fresh‑keeping effect，three kinds of cut chrysanthemum Youxiang，Huangxiao and Baizhou were used as experimental materials，and three treatments were set up，light group（light 16 h/dark 8 h，distilled water），dark stress group（light 0 h/dark 24 h，distilled water）and dark relief group（light 0 h/dark 24 h，20 μmol/L melatonin），to study the alleviation effect of melatonin on leaf yellowing and senescence under dark stress. The results showed that，exogenous melatonin obviously delayed the flower diameter opening，improved water balance value and pigment content of cut chrysanthemum Youxiang，slowed down the change rate of fresh quality of cut flowers，enhanced the activities of SOD（superoxide dismutase）and POD（peroxidase），increased the content of soluble protein and decreased the relative electrical conductivity.Compared with the control，compound solution had the best preservation effect on Youxiang cut flowers（After 7 days of treatment，the average flower diameter was 7.11 cm，which was the smallest，and the flowers could continue to bloom），followed by 20 μmol/L melatonin and basic vase solution. For dark treatment，melatonin treatment increased the contents of chlorophyll and carotenoid in three cut chrysanthemum leaves under dark stress，delayed the degradation rate of soluble protein，and decreased the relative electrical conductivity and malondialdehyde content. On the 7th day of storage，the relative conductivity and malondialdehyde content of cut chrysanthemum in dark relief group decreased the most compared with that in dark stress group，with Youxiang decreased by 13.76% and 12.12%，Huangxiao by 17.35% and 12.47%，and Baizhou by 10.64% and 13.28%，all reaching significant levels（P<0.05）. 20 μmol/L melatonin could alleviate the dark stress in cut chrysanthemum leaves. It is concluded that melatonin can decrease the content of MDA by enhancing the activity of antioxidant enzymes in cut chrysanthemum，so as to alleviate the dark stress and prolong the green period of leaves，which provides theoretical basis for the application of melatonin in long‑distance transportation of cut chrysanthemum.

Key words: Melatonin, Cut chrysanthemum flowers, Physiological property, Preservation, Dark stress

摘要： 为提升切花菊的贮运性，将优香鲜切花枝插于蒸馏水（对照）、基础瓶插液（30 g/kg蔗糖+250 mg/L 8-羟基喹啉+200 mg/L柠檬酸）、褪黑素瓶插液（20 μmol/L褪黑素）、基础+褪黑素复合液（20 μmol/L褪黑素＋30 g/kg蔗糖+250 mg/L 8-羟基喹啉+200 mg/L柠檬酸）中，探索褪黑素对切花菊的保鲜效应。基于前面保鲜效应结果，以优香、黄小、白舟鲜切花枝为试验材料，设光照组（光照16 h/黑暗8 h，蒸馏水）、黑暗胁迫组（光照0 h/黑暗24 h，蒸馏水）、黑暗缓解组（光照0 h/黑暗24 h，20 μmol/L褪黑素）3个处理，研究褪黑素对3种切花菊黑暗胁迫下叶片黄化衰老的缓解效应。结果表明，添加褪黑素能够明显延缓切花菊优香花径张开度，提升水分平衡值，提高色素含量，减缓切花鲜质量变化率下降速度，增强超氧化物歧化酶（SOD）和过氧化物酶（POD）的活性，增加可溶性蛋白含量，降低相对电导率。与对照瓶插液（蒸馏水）相比，基础+褪黑素复合瓶插溶液对优香切花的保鲜效果最好（处理第7天花径平均值最小，为7.11 cm，可继续开放），其次是20 μmol/L褪黑素瓶插溶液和基础瓶插溶液。褪黑素处理提高了黑暗胁迫下3种切花菊叶片叶绿素和类胡萝卜素含量，延缓了切花菊叶片可溶性蛋白的降解速度，降低了相对电导率和丙二醛（MDA）含量，在处理第7天，黑暗缓解组相对电导率和MDA含量与黑暗胁迫组相比均降低最多，优香分别为13.76%、12.12%，黄小分别为17.35%、12.47%，白舟分别为10.64%、13.28%，差异均达到显著水平（P<0.05），20 μmol/L褪黑素可以缓解切花菊叶片黑暗胁迫。推断褪黑素通过提高切花菊抗氧化酶活性等从而降低MDA含量，以缓解黑暗胁迫，从而延长叶绿期。

关键词: 褪黑素, 菊花切花, 生理特性, 保鲜, 黑暗胁迫