Effects of γ-Aminobutyric Acid and Melatonin on Growth and Cadmium Accumulation of Peach Seedlings under Cadmium Stress

Objective This study aimed to explore the effects of exogenous γ-aminobutyric acid (GABA) and melatonin on the growth and cadmium (Cd) accumulation in peach seedlings under Cd stress, and to identify the methods of reducing cadmium accumulation in peach trees.

Method Peach seedlings were used as experimental materials, a pot experiment was conducted, in which the seedlings were treated with foliar spraying of 150 μmol L⁻¹ melatonin and irrigation with 0.5 mmol L⁻¹ GABA to investigate the effects of melatonin and GABA on the growth and Cd accumulation in peach seedlings under 0.1 mg L⁻¹ Cd stress.

Result Under Cd stress, GABA, melatonin and GABA + melatonin treatments increased the plant height, biomass and photosynthetic pigments (chlorophyll a, chlorophyll b, total chlorophyll, and carotenoid) contents of peach seedlings to a certain extent, and changed the nutrient absorption of peach seedlings. In addition, GABA and GABA + melatonin treatments decreased the contents of Cd in root and shoot of peach seedlings, while melatonin treatment only reduced Cd in root and had no significant effect on Cd in shoot. Compared with Cd treatment, GABA and GABA + melatonin treatments decreased Cd in shoot in peach seedlings by 21.85% and 26.99%, respectively.

Conclusion Under Cd stress, GABA, melatonin and GABA + melatonin treatments can promote the growth of peach seedlings, and GABA and GABA + melatonin treatment can also reduce the Cd accumulation in peach seedlings.