The present study designed to illustrate correlation between cadmium induced stress and plant growth, photosynthetic pigments, morphological and physiological attributes. To study these parameters 2 weeks old seedling of B. juncea were subjected to 50 µM Cd, 100 µM Cd and 100 µM SNP separately and in combination with SNP. After 96 h, the treated plant were harvested to analyze the cellular homeostasis and metal tolerance mechanism via examining growth, stress parameters, enzymatic and non enzymatic antioxidants and expression level of NR. Higher level of Cd (100 µM) significantly increased accumulation of reactive oxygen species and malonaldehyde content in comparison to 50 µM Cd. Exogenous supplementation of SNP (100 µM) to 50 µM Cd treated plant had an additive effect on plant growth by improving the level of proline, photosynthetic pigments and activities of enzymatic antioxidants which was confirmed by histochemical staining for NADPH-d and NO fluorescence from DAF-DA staining in roots of B. juncea. Applying SNP to 50 µM Cd exposed B. juncea roots enhanced NR activity by 1.36 folds and increased NO production by 1.12 folds than individual Cd treated roots. In addition, semi quantitative RT-PCR study revealed the induction of BjNR was more pronounced in 50 µM Cd treated roots in comparison to 100 µM Cd treated roots. The present finding revealed NO confers increased B. juncea tolerance to Cd stress by stimulation of antioxidants and reestablishment of cellular redox status. Different biochemical analysis showed that plant growth, photosynthetic pigment and antioxidants were positively correlated with NO and it’s negatively correlated with oxidative stress biomarkers. Therefore, NO is gaseous signalling molecule with potential role in Cd detoxification mechanism in B. juncea.

本研究旨在说明镉诱导的胁迫与植物生长、光合色素、形态和生理属性之间的相关性。为了研究芥菜2 周龄幼苗的这些参数分别和与 SNP 结合使用 50 µM Cd、100 µM Cd 和 100 µM SNP。96 小时后，收获处理过的植物，通过检查生长、胁迫参数、酶促和非酶促抗氧化剂以及 NR 的表达水平来分析细胞稳态和金属耐受机制。与 50 µM Cd 相比，较高水平的 Cd (100 µM) 显着增加了活性氧和丙二醛含量的积累。外源性补充 SNP (100 µM) 到 50 µM Cd 处理的植物通过提高脯氨酸水平、光合色素和酶促抗氧化剂的活性对植物生长产生累加作用，这通过 NADPH-d 的组织化学染色和 DAF 的 NO 荧光证实-芥菜根中的 DA 染色. 将 SNP 应用于暴露于 50 µM Cd 的芥菜根，NR 活性提高了 1.36 倍，NO 产量比单个 Cd 处理的根提高了 1.12 倍。此外，半定量 RT-PCR 研究表明，与 100 µM Cd 处理的根相比，50 µM Cd 处理的根中BjNR的诱导更明显。目前的发现表明 NO 增加了芥菜通过刺激抗氧化剂和重建细胞氧化还原状态来耐受镉胁迫。不同的生化分析表明，植物生长、光合色素和抗氧化剂与NO呈正相关，与氧化应激生物标志物呈负相关。因此，NO 是一种气态信号分子，在芥菜Cd 解毒机制中具有潜在作用。