Gamma-aminobutyric acid (GABA) can mediate plant stress tolerance. The objective of this study was to examine the effects of GABA on seed germination, seedling growth, ion elements, and carbohydrate and antioxidant metabolism in perennial ryegrass (Lolium perenne L.) cultivar ‘Inspire’ exposed to salinity stress. Seed germination percentage was significantly reduced by 175 mM NaCl, but 1 mM GABA added to the salinity treatment (GABA + NaCl) substantially improved germination (78%) compared to the NaCl treatment alone (46%). Compared to the non-stressed control, seedling length, shoot fresh weight, shoot dry weight, shoot carbon, and shoot nitrogen concentrations decreased under 175 mM NaCl, but such reductions were significantly lower in seedlings treated with GABA + NaCl. Salinity stress increased Na⁺ and did not alter K⁺ concentrations in the shoots, but GABA had no effect on both ions under the stress condition. The increased shoot glucose and fructose and unchanged sucrose concentrations were shown in the seedlings under the NaCl stress, and NaCl + GABA treatment had significantly higher glucose and lower sucrose but the same fructose concentrations, compared to the NaCl treatment alone. Salinity stress increased the activity of shoot superoxide dismutase (SOD) and decreased catalase (CAT) and ascorbate peroxidase (APX) activities, but higher CAT activity and unchanged SOD and APX activities were observed in the NaCl + GABA treatment, compared to the NaCl treatment alone. The results indicated that GABA ameliorated salinity tolerance by improving seed germination, seedling growth, and C and N status and altering carbohydrate and antioxidant metabolism.

γ-氨基丁酸（GABA）可以介导植物的逆境耐受性。本研究的目的是检查 GABA 对暴露于盐分胁迫的多年生黑麦草 ( Lolium perenne L.) 栽培品种“Inspire”的种子萌发、幼苗生长、离子元素以及碳水化合物和抗氧化剂代谢的影响。175 mM NaCl 显着降低了种子发芽百分比，但与单独的 NaCl 处理 (46%) 相比，在盐度处理 (GABA + NaCl) 中添加 1 mM GABA 显着改善了发芽率 (78%)。与未受胁迫的对照相比，幼苗长度、枝条鲜重、枝条干重、枝条碳和枝条氮浓度在 175 mM NaCl 下降低，但在用 GABA + NaCl 处理的幼苗中，这种降低显着降低。盐胁迫增加 Na⁺并且没有改变 K ⁺芽中的浓度，但 GABA 在胁迫条件下对两种离子都没有影响。在 NaCl 胁迫下，幼苗中的芽葡萄糖和果糖浓度增加，蔗糖浓度不变，与单独的 NaCl 处理相比，NaCl + GABA 处理具有显着更高的葡萄糖和更低的蔗糖，但果糖浓度相同。盐胁迫增加了地上部超氧化物歧化酶 (SOD) 的活性，降低了过氧化氢酶 (CAT) 和抗坏血酸过氧化物酶 (APX) 的活性，但与 NaCl 处理相比，NaCl + GABA 处理观察到更高的 CAT 活性和不变的 SOD 和 APX 活性独自的。结果表明，GABA 通过改善种子发芽、幼苗生长和 C 和 N 状态以及改变碳水化合物和抗氧化剂代谢来改善耐盐性。