Arsenic (As) polluted food chain has become a serious issue for the growth and development of humans, animals and plants. Nitric oxide (NO) or silicon (Si) may mitigate As toxicity. However, the combined application of NO and Si in mitigating As uptake and phytotoxicity in Brassica juncea is unknown. Hence, the collegial effect of sodium nitroprusside (SNP), a NO donor and Si application on B. juncea growth, gas exchange parameters, antioxidant system and As uptake was examined in a greenhouse experiment. Arsenic toxicity injured cell membrane as signposted by the elevated level of malondialdehyde (MDA) and hydrogen peroxide (H₂O₂), thus decreasing the growth of stressed plants. Moreover, As stress negatively affected gas exchange parameters and antioxidative system of plants. However, NO or/and Si alleviated As induced oxidative stress through increasing the activity of superoxide dismutase (SOD), ascorbate peroxidase (APX), glutathione reductase (GR), glutathione S-transferase (GST), glutathione (GSH), along with thiol and proline synthesis. Furthermore, plants treated with co-application of NO and Si showed improved growth, gas attributes and decreased As uptake under As regimes. The current study highlights that NO and Si synergistically interact to mitigate detrimental effects of As stress through reducing As uptake. Our findings recommend combined NO and Si application in As spiked soils for improvement of plant growth and stress alleviation.

砷（As）污染的食物链已成为人类、动植物生长发育的严重问题。一氧化氮 (NO) 或硅 (Si) 可以减轻砷的毒性。然而，NO 和 Si 的联合应用在减轻芥菜As 吸收和植物毒性方面尚不清楚。因此，在温室实验中检查了硝普钠（SNP）、NO 供体和硅的应用对芥菜生长、气体交换参数、抗氧化系统和砷吸收的协同效应。砷毒性会损伤细胞膜，其标志是丙二醛 (MDA) 和过氧化氢 (H ₂ O ₂ ) 水平升高，从而降低受胁迫植物的生长。此外，砷胁迫对植物的气体交换参数和抗氧化系统产生负面影响。然而，NO或/和Si通过增加超氧化物歧化酶（SOD）、抗坏血酸过氧化物酶（APX）、谷胱甘肽还原酶（GR）、谷胱甘肽S-转移酶（GST）、谷胱甘肽（GSH）以及硫醇和脯氨酸的合成。此外，共同施用 NO 和 Si 处理的植物在 As 处理下表现出生长、气体属性的改善和 As 吸收的减少。目前的研究强调，NO 和 Si 协同相互作用，通过减少砷的吸收来减轻砷胁迫的有害影响。我们的研究结果建议在掺砷土壤中联合施用 NO 和 Si，以改善植物生长并缓解胁迫。