ABSTRACT

Selenium (Se) causes oxidative damage to plants. Proline is accumulated as a compatible solute in plants under stress conditions and mitigates stresses. Selenate at 250 µM increased cell death and inhibited the growth of tobacco BY-2 cells while exogenous proline at 10 mM did not mitigate the inhibition by selenate. Selenate increased accumulation of Se and ROS and activities of antioxidant enzymes but not lipid peroxidation in the BY-2 cells. Proline increased Se accumulation and antioxidant enzyme activities but not either ROS accumulation or lipid peroxidation in the selenate-stressed cells. Glutathione (GSH) rather than ascorbic acid (AsA) mitigated the growth inhibition although both reduced the accumulation of ROS induced by selenate. These results indicate that proline increases both antioxidant enzyme activities and Se accumulation, which overall fails to ameliorate the growth inhibition by selenate and that the growth inhibition is not accounted for only by ROS accumulation.

Abbreviations: APX: ascorbate peroxidase; AsA: ascorbic acid; BY-2: Bright Yellow-2; CAT: catalase; DAI: days after inoculation; DW: dry weight; FW: fresh weight; GSH: glutathione; ROS: reactive oxygen species

摘要

硒（Se）对植物造成氧化损伤。脯氨酸在胁迫条件下作为相容性溶质在植物中积累，可以缓解胁迫。250 µM的硒酸盐可增加细胞死亡并抑制烟草BY-2细胞的生长，而10 mM的外源脯氨酸不能减轻硒酸盐的抑制作用。硒酸盐增加了Se和ROS的积累以及抗氧化酶的活性，但没有增加BY-2细胞中脂质的过氧化作用。脯氨酸增加了硒酸盐胁迫细胞中硒的积累和抗氧化酶的活性，但无ROS积累或脂质过氧化作用。谷胱甘肽（GSH）而不是抗坏血酸（AsA）减轻了生长抑制作用，尽管两者都减少了硒酸盐诱导的ROS的积累。这些结果表明脯氨酸增加了抗氧化酶的活性和硒的积累，

缩写： APX：抗坏血酸过氧化物酶；AsA：抗坏血酸；BY-2：鲜黄2；CAT：过氧化氢酶；DAI：接种后几天；DW：干重；FW：鲜重；GSH：谷胱甘肽；ROS：活性氧