Melatonin, as a plant growth regulator, is involved in plant stress resistance. We studied the effects of different concentrations (0, 10, 50, 100, 150, and 200 µmol · L⁻¹) of melatonin on the growth and physiological characteristics of strawberry under cadmium (Cd) stress. The results represented that the growth of strawberry seedlings was inhibited under Cd stress, and the seedling biomass, chlorophyll content and the activities of antioxidant enzymes such as superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), and ascorbate peroxidase (APX) decreased. These toxic effects were, however, effectively remediated by exogenous melatonin pretreatment. Melatonin treatment slowed the inhibitory effect of seedling growth and significantly increased seedling biomass, chlorophyll content, antioxidant enzyme activities, and soluble protein levels in leaves and roots compared with the control. Melatonin treatment also reduced the malondialdehyde (MDA) content and the oxidative stress reactions, increased the anthocyanin content, and slowed the senescence rate, thereby reducing the toxic effects of Cd on strawberries. This indicates that foliar application of melatonin can effectively remediate the adverse effects of Cd on strawberry seedlings; the greatest effect was obtained with melatonin concentration of 100 µmol · L⁻¹.

褪黑激素作为植物生长调节剂，参与植物抗逆性。我们研究了不同浓度（0、10、50、100、150和200 µmol·L ^-1的影响褪黑素对镉（Cd）胁迫下草莓生长和生理特性的影响 结果表明，镉胁迫下草莓幼苗的生长受到抑制，幼苗的生物量，叶绿素含量以及抗氧化物酶的活性如超氧化物歧化酶（SOD），过氧化物酶（POD），过氧化氢酶（CAT）和抗坏血酸过氧化物酶（ APX）减少。然而，这些毒性作用已通过外源褪黑激素预处理得到有效地补救。与对照相比，褪黑素处理减慢了幼苗生长的抑制作用，并显着增加了幼苗生物量，叶绿素含量，抗氧化酶活性以及叶和根中的可溶性蛋白水平。褪黑素处理还降低了丙二醛（MDA）含量和氧化应激反应，增加花青素含量，减慢衰老速度，从而降低镉对草莓的毒性作用。这表明叶面施用褪黑激素可以有效地缓解镉对草莓幼苗的不利影响。褪黑激素浓度为100 µmol·L时效果最佳^-1。