Department of Biology, Xinzhou Teachers University, Xinzhou, Shanxi 034000, China.
Biosci Rep. 2024 Jun 26;44(6). doi: 10.1042/BSR20240215.
Increasing cadmium (Cd) pollution has negative effects on quinoa growth and production. Gamma-aminobutyric acid (GABA) confers plants with stress resistance to heavy metals; however, the mechanism remains unclear. We explored the effects of exogenous GABA on the physiological characteristics, antioxidant capacity, and Cd accumulation of quinoa seedlings under Cd stress using hydroponic experiments. Partial least-squares regression was used to identify key physical and chemical indices of seedlings affecting Cd accumulation. Compared with those of the CK group, exposure to 10 and 25 µmol·L-1 Cd significantly reduced the photosynthetic pigment contents, photosynthesis, and biomass accumulation of quinoa seedlings; resulted in shorter and thicker roots; decreased the length of the lateral roots; decreased the activities of superoxide dismutase (SOD) and peroxide (POD); and increased H2O2 and malondialdehyde (MDA) contents. Exogenous GABA reduced the Cd content in the stem/leaves and roots of quinoa seedlings under Cd stress by 13.22-21.63% and 7.92-28.32%, decreased Cd accumulation by 5.37-6.71% and 1.91-4.09%, decreased the H2O2 content by 38.21-47.46% and 45.81-55.73%, and decreased the MDA content by 37.65-48.12% and 29.87-32.51%, respectively. GABA addition increased the SOD and POD activities in the roots by 2.78-5.61% and 13.81-18.33%, respectively, under Cd stress. Thus, exogenous GABA can reduce the content and accumulation of Cd in quinoa seedlings by improving the photosynthetic characteristics and antioxidant enzyme activity and reducing the degree of lipid peroxidation in the cell membrane to alleviate the toxic effect of Cd stress on seedling growth.
镉（Cd）污染增加对藜麦生长和产量有负面影响。γ-氨基丁酸（GABA）赋予植物对重金属的抗逆性；然而，其机制尚不清楚。我们通过水培实验研究了外源 GABA 对 Cd 胁迫下藜麦幼苗生理特性、抗氧化能力和 Cd 积累的影响。偏最小二乘回归用于鉴定影响 Cd 积累的幼苗关键物理和化学指标。与 CK 组相比，暴露于 10 和 25 μmol·L-1 Cd 显著降低了藜麦幼苗的光合色素含量、光合作用和生物量积累；导致根更短、更粗；减少了侧根的长度；降低了超氧化物歧化酶（SOD）和过氧化物酶（POD）的活性；并增加了 H2O2 和丙二醛（MDA）的含量。外源 GABA 降低了 Cd 胁迫下藜麦幼苗茎/叶和根中 Cd 的含量 13.22-21.63%和 7.92-28.32%，减少了 Cd 积累 5.37-6.71%和 1.91-4.09%，降低了 H2O2 含量 38.21-47.46%和 45.81-55.73%，降低了 MDA 含量 37.65-48.12%和 29.87-32.51%。GABA 加 Cd 胁迫下，根中 SOD 和 POD 活性分别增加了 2.78-5.61%和 13.81-18.33%。因此，外源 GABA 通过提高光合特性和抗氧化酶活性，降低细胞膜脂质过氧化程度，减少 Cd 对幼苗生长的毒害作用，降低藜麦幼苗中 Cd 的含量和积累。
