Common centaury (Centaurium erythraea Rafn.) is a plant species that can inhabit saline soils. It is known as a plant with high spontaneous regeneration potential in vitro. In the present work we evaluated shoots and roots salinity tolerance of non‐transformed and three AtCKX transgenic centaury lines to graded NaCl concentrations (0, 50, 100, 150, 200 mM) in vitro. Overexpression of AtCKX genes in transgenic centaury plants resulted in an altered cytokinins (CKs) profile leading to a decline of bioactive CK levels and, at the same time, increased contents of storage CK forms, inactive CK forms and/or CK nucleotides. Significant increment of fresh shoot weight was obtained in shoots of non‐transformed and AtCKX1 transgenic line only on medium supplemented with 50 mM NaCl. However two analysed AtCKX2 transgenic lines reduced shoot growth at all NaCl concentrations. In general, centaury roots showed higher tolerance to salinity than shoots. Non‐transformed and AtCKX1 transgenic lines tolerated up to 100 mM NaCl without change in frequency of regeneration and number of regenerated plants. Roots of two analysed AtCKX2 transgenic lines showed different regeneration potential under salt stress. Regeneration of transgenic AtCKX2‐26 shoots even at 200 mM NaCl was recorded. Salinity stress response of centaury shoots and roots was also evaluated at biochemical level. Free proline, malondialdehyde and hydrogen peroxide content as well as antioxidative enzymes activities were investigated in shoots and roots after 1, 2, 4 and 8 weeks. In general, adition of NaCl in culture medium elevated all biochemical parameters in centaury shoots and in roots. Considering that all analysed AtCKX transgenic centaury lines showed altered salt tolerance to graded NaCl concentrations in vitro it can be assumed that CKs might be involved in plant defence to salt stress conditions.

中文翻译：

---

非转化和AtCKX转基因种（Centaurium erythraea Rafn。）幼芽和根的盐分胁迫响应

常见的世纪（Centaurium erythraea Rafn。）是一种可以居住在盐渍土壤中的植物。它被称为具有高自发再生潜力的植物。在目前的工作中，我们在体外评估了未转化的和三个AtCKX转基因世纪系对NaCl分级浓度（0、50、100、150、200 mM）的芽和根盐度耐受性。AtCKX基因在转基因植物中的过度表达导致细胞分裂素（CKs）谱改变，从而导致生物活性CK水平下降，同时，存储CK形式，非活性CK形式和/或CK核苷酸含量增加。在未转化和AtCKX1的芽中，鲜芽重量显着增加转基因品系仅在添加了50 mM NaCl的培养基上进行。然而，两个分析的AtCKX2转基因品系在所有NaCl浓度下均降低了枝条的生长。一般而言，百年生根对盐分的耐受性高于芽。未转化的和AtCKX1转基因品系最高耐受100 mM NaCl，而没有改变再生频率和再生植物的数量。在盐胁迫下，两个分析的AtCKX2转基因品系的根显示出不同的再生潜力。转基因AtCKX2的再生‐26即使在200 mM NaCl中也能记录芽。还从生化水平评估了百年生芽和根的盐分胁迫响应。在1、2、4和8周后，在茎和根中研究了脯氨酸，丙二醛和过氧化氢的含量以及抗氧化酶的活性。通常，在培养基中添加氯化钠会提高百年生芽和根中的所有生化参数。考虑到所有分析的AtCKX转基因百年种系均显示出盐分耐受性随NaCl分级浓度的变化而变化，可以认为CKs可能参与了植物对盐胁迫的防御。