College of Life Science and Technology, Central South University of Forestry and Technology, Changsha, 410004, PR China.
College of Life Science and Technology, Central South University of Forestry and Technology, Changsha, 410004, PR China.
Chemosphere. 2023 Oct;339:139768. doi: 10.1016/j.chemosphere.2023.139768. Epub 2023 Aug 9.
Arbuscular mycorrhizal fungi (AMF) can alleviate heavy metal phytotoxicity and promote plant growth, while the underlying mechanisms of AMF symbiosis with host plants under manganese (Mn) stress remain elusive. A pot experiment was carried out to investigate the plant growth, micro-structure, Mn accumulation, subcellular distribution, chemical forms, and physiological and biochemical response of Rhus chinensis inoculated with Funneliformis mosseae (FM) under different Mn treatments. The results showed that compared with plants without FM, FM-associated plants exhibited higher growth status, photosynthetic pigments, and photosynthesis under Mn stress. FM-associated plants were able to maintain greater integrity in mesophyll structure, higher thickness of leaf, upper epidermis, and lower epidermis under Mn treatment, and promote leaf growth. Mn accumulation in leaves (258.67-2230.50 mg kg), stems (132.67-1160.00 mg kg), and roots (360.92-2446.04 mg kg) of the seedlings inoculated with FM was higher than non-inoculated ones. FM-associated plants exhibited higher osmotic regulating substances and antioxidant enzymes' activities under Mn exposure, suggesting lower Mn toxicity in FM inoculated seedlings, despite the augment in Mn accumulation. After FM inoculation, Mn concentration (151.04-1211.32 mg kg) and percentage (64.41-78.55%) enhanced in the cell wall, whilst the transport of Mn to aerial plant organs decreased. Furthermore, FM symbiosis favored the conversion of Mn from high toxic forms (2.17-15.68% in F, 11.37-24.52% in F) to inactive forms (28.30-38.15% in F, 18.07-28.59% in F, 4.41-17.99% in F) with low phytotoxicity. Our study offers a theoretical basis for remediation of the FM- R. chinensis symbiotic system in Mn-contaminated environments.
丛枝菌根真菌（AMF）可以减轻重金属的植物毒性并促进植物生长，而在锰（Mn）胁迫下 AMF 与宿主植物共生的潜在机制仍不清楚。采用盆栽实验研究了接种摩西管柄囊霉（FM）后火炬松在不同 Mn 处理下的生长状况、微观结构、Mn 积累、亚细胞分布、化学形态以及生理生化响应。结果表明，与未接种 FM 的植株相比，接种 FM 的植株在 Mn 胁迫下具有更高的生长状态、光合色素和光合作用。FM 接种植株在 Mn 处理下能够保持较大的叶肉结构完整性、较厚的叶片、上表皮和下表皮，促进叶片生长。接种 FM 的幼苗叶片（258.67-2230.50 mg kg）、茎（132.67-1160.00 mg kg）和根（360.92-2446.04 mg kg）中的 Mn 积累量高于未接种的植株。FM 接种植株在 Mn 暴露下表现出较高的渗透调节物质和抗氧化酶活性，表明 FM 接种幼苗中的 Mn 毒性较低，尽管 Mn 积累量增加。接种 FM 后，Mn 浓度（151.04-1211.32 mg kg）和比例（64.41-78.55%）在细胞壁中增加，而 Mn 向气生植物器官的运输减少。此外，FM 共生有利于将 Mn 从高毒性形态（F 中 2.17-15.68%，F 中 11.37-24.52%）转化为低毒性的非活性形态（F 中 28.30-38.15%，F 中 18.07-28.59%，F 中 4.41-17.99%）。本研究为在 Mn 污染环境中修复 FM-R. chinensis 共生系统提供了理论依据。
