In this study, the effects of excess NH₄⁺-N on the subcellular accumulation of O₂⁻ and H₂O₂ in submerged plant Hydrilla verticillata (L.f.) Royle were investigated using both histochemical and cytochemical methods. Treatments with ≥ 2.00 and ≥ 5.00 mg L⁻¹ NH₄⁺-N for 5 d significantly increased production of O₂⁻ and H₂O₂, respectively. The activities of plasma membrane-bound NADPH (nicotinamide adenine dinucleotide phosphate) oxidases and antioxidant enzymes (superoxide dismutase, peroxidase, ascorbate peroxidase, catalase, dehydroascorbate reductase and glutathione reductase) were also increased correspondingly. This study also provides the first cytochemical evidence of subcellular accumulation of O₂⁻ and H₂O₂ in the submerged plants. In the leaves of H. verticillata treated with 20.0 mg L⁻¹ NH₄⁺-N, O₂⁻ dependent DAB precipitates were found primarily on the inner side of the plasma membrane, extracellular space and chloroplasts. H₂O₂-CeCl₃ precipitates were mainly localized on the inner side of the plasma membrane and extracellular space of the mesophyll cells. Treatments with the inhibitors of NADPH oxidase (diphenylene iodonium and imidazole) indicate that NH₄⁺-N-induced production of O₂⁻ and H₂O₂ in H. verticillata leaves may involve plasma membrane-bound NADPH oxidase. Moreover, low-light treatment decreased NH₄⁺-induced O₂⁻ production, suggesting that alterations in the photosynthetic electron transfer chain due to NH₄⁺ toxicity could lead to O₂⁻ production.

在这项研究中，过量的NH的影响₄ ⁺ -N O对的亚细胞积累₂ ^-和H ₂ ö ₂在浸没植物黑藻（LF）柏枝同时使用组织化学和组织化学的方法进行了研究。与≥2.00和5.00≥毫克的L处理^-1 NH ₄ ⁺ -N 5 d显著产量增加的O- ₂ ^-和H ₂ ö ₂， 分别。质膜结合的NADPH（烟酰胺腺嘌呤二核苷酸磷酸）氧化酶和抗氧化酶（超氧化物歧化酶，过氧化物酶，抗坏血酸过氧化物酶，过氧化氢酶，脱氢抗坏血酸还原酶和谷胱甘肽还原酶）的活性也相应增加。这项研究还提供的O亚积累的第一个细胞化学证据₂ ^-和H ₂ Ø ₂中的沉水植物。在叶黑藻20.0毫克的L处理^-1 NH ₄ ⁺ -N，O- ₂ ^-被发现主要在质膜上，细胞外空间和叶绿体的内侧依赖DAB沉淀。H₂ O ₂ -CeCl ₃沉淀主要位于质膜的内侧和叶肉细胞的细胞外空间。与NADPH氧化酶（二亚苯基碘和咪唑）的抑制剂的治疗表明，NH ₄ ⁺ -N诱导生产的O ₂ ^-和H ₂ ö ₂在藻H.叶片可涉及等离子体膜结合的NADPH氧化酶。此外，低光治疗降低NH ₄ ⁺诱导ö ₂ ^-生产，这表明在光合电子传递链，其改变由于NH ₄ ⁺毒性可能导致与O ₂ ^-生产。