A study was performed to assess if nitrate reductase (NR) participated in brassinosteroid (BR)-induced cadmium (Cd) stress tolerance primarily by accelerating the ascorbate-glutathione (AsA-GSH) cycle. Prior to initiating Cd stress (CdS), the pepper plants were sprayed with 0.5 μM 24-epibrassinolide (EBR) every other day for 10 days. Thereafter the seedlings were subjected to control or CdS (0.1 mM CdCl₂) for four weeks. Cadmium stress decreased the plant growth related attributes, water relations as well as the activities of monodehydroascorbate reductase (MDHAR) and dehydroascorbate reductase (DHAR), but enhanced proline content, leaf Cd²⁺ content, oxidative stress-related traits, activities of ascorbate peroxidase (APX) and glutathione reductase (GR), and the activities of antioxidant defence system-related enzymes as well as NR activity and endogenous nitric oxide content. EBR reduced leaf Cd²⁺ content and oxidative stress-related parameters, enhanced plant growth, regulated water relations, and led to further increases in proline content, AsA-GSH cycle-related enzymes’ activities, antioxidant defence system-related enzymes as well as NR activity and endogenous nitric oxide content. The EBR and the inhibitor of NR (tungstate) reversed the positive effects of EBR by reducing NO content, showing that NR could be a potential contributor of EBR-induced generation of NO which plays an effective role in tolerance to CdS in pepper plants by accelerating the AsA-GSH cycle and antioxidant enzymes.

进行了一项研究，以评估硝酸盐还原酶（NR）是否通过加速抗坏血酸谷胱甘肽（AsA-GSH）周期参与了油菜素类固醇（BR）诱导的镉（Cd）胁迫耐受性。在开始Cd胁迫（CdS）之前，每隔一天用0.5μM24-表油菜素内酯（EBR）喷洒辣椒植株10天。此后，将幼苗进行对照或CdS（0.1 mM CdCl ₂）处理四周。镉胁迫降低了植物生长相关的属性，水分关系以及单脱氢抗坏血酸还原酶（MDHAR）和脱氢抗坏血酸还原酶（DHAR）的活性，但脯氨酸含量增加，叶片Cd ^2+增加。含量，氧化应激相关性状，抗坏血酸过氧化物酶（APX）和谷胱甘肽还原酶（GR）的活性以及抗氧化防御系统相关酶的活性以及NR活性和内源性一氧化氮含量。EBR还原叶片Cd ²⁺含量和氧化应激相关参数，增强植物生长，调节水关系，并导致脯氨酸含量，AsA-GSH循环相关酶的活性，抗氧化防御系统相关酶以及NR活性和内源性一氧化氮的进一步增加内容。EBR和NR抑制剂（钨酸盐）通过降低NO含量逆转了EBR的积极作用，表明NR可能是EBR诱导的NO生成的潜在原因，它通过促进辣椒植物对CdS的耐受性发挥了有效作用AsA-GSH循环和抗氧化酶。