• 关键词：胡杨  SO₂  ABA  H₂O₂  NO

• 基金项目：国家自然科学基金（No.31500504，31371868）；山西省高等学校科技创新项目（No.2017102）

• 韩彦莎
• 山西大学生命科学学院, 太原 030006

• 杨浩
• 山西大学生命科学学院, 太原 030006

• 仪慧兰
• 山西大学生命科学学院, 太原 030006

• 摘要：二氧化硫（SO₂）是一种常见的大气污染物.前期研究表明，过氧化氢（H₂O₂）和一氧化氮（NO）参与调控SO₂诱导的胡杨细胞毒性.脱落酸（ABA）是一种植物逆境激素，目前关于ABA在植物细胞响应SO₂胁迫中的具体作用并不清楚.因此，本文以胡杨愈伤细胞为材料，采用SO₂衍生物处理，研究外源ABA在植物细胞SO₂毒性缓解中的作用及相关机制.结果发现：2 mmol·L^-1 SO₂衍生物处理胡杨细胞9 h后，细胞电解质外渗率和细胞死亡率明显增加；外源施用5 μmol·L^-1 ABA可明显缓解SO₂对胡杨细胞的毒性，降低电解质外渗率和细胞死亡率.2 mmol·L^-1 SO₂衍生物胁迫下，与SO₂单独处理组相比，添加外源ABA能够使胡杨细胞的抗坏血酸过氧化物酶（APX）和过氧化氢酶（CAT）活性分别提高23.9%和48.0%，从而减少胞内H₂O₂水平.此外，SO₂胁迫下，外施ABA后胡杨细胞的PeNia1、PeNia2基因表达受到明显抑制，细胞硝酸还原酶（NR）活性降低24.1%，胞内NO合成减少.以上结果表明，SO₂胁迫下，外源施加ABA可有效降低胡杨细胞内H₂O₂和NO水平，从而缓解SO₂对胡杨细胞的毒性.

• Abstract：Sulfur dioxide (SO₂) is a common air pollutant. Previous studies revealed that hydrogen peroxide (H₂O₂) and nitric oxide (NO) regulated SO₂-induced cell toxicity of Populus euphratica. Abscisic acid (ABA) is a phytohormone involved in plant response to abiotic stress. To date, the role of ABA in cell responses to SO₂ stress is largely unknown. In the present study, using SO₂ derivatives treatment, we investigated the relevant mechanisms of exogenous ABA alleviation of SO₂-induced toxicity in P. euphratica callus cells. The results showed that 2 mmol·L^-1 SO₂ derivatives treatment (9 h) caused significant increase of cell death and electrolyte leakage rate of P. euphratica cells. Exogenous ABA (5 μmol·L^-1) application could alleviate SO₂-induced toxicity, decreasing the cell death rate and electrolyte leakage rate. Under 2 mmol·L^-1 SO₂ derivatives exposure, exogenous ABA enhanced the activity of ascorbate peroxidase (APX) and catalase (CAT) by 23.9% and 48.0%, compared with SO₂ treatment alone, respectively, contributing to the scavenging of H₂O₂ within P. euphratica cells. Furthermore, exogenous ABA could remarkably inhibit PeNia1 and PeNia2 gene expression, and decrease nitrate reductase (NR) activity by 24.1%, thus restricted NO generation within P. euphratica cells. These results suggested that exogenously applied ABA could alleviate SO₂-induced toxicity by reducing H₂O₂ and NO level in P. euphratica cells.

• Key words：Populus euphratica  SO₂  ABA  H₂O₂  NO

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