Institute of Botany, University of the Punjab, Quaid-e-Azam Campus, Lahore, 54590, Pakistan.
Department of Botany, Faculty of Science, Fayoum University, Fayoum, 63514, Egypt.
BMC Microbiol. 2024 Aug 14;24(1):304. doi: 10.1186/s12866-024-03453-8.
Ectomycorrhizal (ECM and ECM-like) structures associated with plant root systems are a challenge for scientists. The dispersion pattern of roots within the soil profile and the nutritional conditions are both favourable factors to motivate the plants to make ECM associations.
This study discusses the colonization of mycorrhizal associations in Kobresia and Polygonum species including Polygonum viviparum, Kobresia filicina, K. myosuroides, Alnus nitida, Betula pendula, Pinus sylvestris, and Trifolium repens grown naturally in cold stressed soils of Gilgit-Baltistan (high-altitude alpine Deosai plains), Hazara, Swat, Dir, and Bajaur. Sieved soil batches were exposed to +5 °C (control), -10, -20, -30, -40, -50, -125 °C for 5 h, and selected plants were sown to these soils for 10 weeks under favourable conditions for ECM colonization. Ectomycorrhizal associations were examined in the above mentioned plants. Some ECM fungi have dark mycelia that look like the mantle and Hartig net. Examples of these are Kobresia filicina, K. myosuroides, and Polygonum viviparum. Findings of this study revealed that K. myosuroides excelled in ECM root tip length, dry mass, and NH concentration at -125 °C. Contrarily, A. nitida demonstrated the lower values, indicated its minimum tolerance. Notably, T. repens boasted the highest nitrogen concentration (18.7 ± 1.31 mg/g), while P. sylvestris led in phosphorus (3.2 ± 0.22 mg/g). The B. pendula showed the highest potassium concentration (9.4 ± 0.66 mg/g), emphasising species-specific nutrient uptake capabilities in extreme cold conditions. The PCA analysis revealed that the parameters, e.g., NH in soil mix (NH), NO in soil mix (NO), phosphorus in soil in species of Polygonum viviparum, Kobresia filicina, K. myosuroides, Alnus nitida, Betula pendula, Pinus sylvestris, and Trifolium repens are most accurately represented in cases of + 5 °C, -10 °C, and -20 °C temperatures. On the other hand, the parameters for ECM root tips (ECM) and Dry Mass (DM) are best described in -40 °C, -50 °C, and - 125 °C temperatures. All parameters have a strong influence on the variability of the system indicated the efficiency of ECM. The heatmap supported the nutrients positively correlated with ECM colonization with the host plants.
At lower temperatures, hyphae and spores in roots were reduced, while soluble phosphorus concentrations of leaves were increased in cold stress soils. Maximum foliar nutrient concentrations were found in K. myosuroides at the lowest temperature treatments due to efficient functioning and colonization of ECM.
与植物根系相关的外生菌根（ECM 和 ECM 样结构）对科学家来说是一个挑战。根在土壤剖面中的分布模式和营养条件都是促使植物形成 ECM 联系的有利因素。
本研究讨论了在吉尔吉特-巴尔蒂斯坦（高寒阿尔卑斯 Deosai 平原）、哈扎拉、斯瓦特、迪尔和巴焦尔的冷胁迫土壤中自然生长的 Kobresia 和 Polygonum 物种（包括 Polygonum viviparum、Kobresia filicina、K. myosuroides、Alnus nitida、Betula pendula、Pinus sylvestris 和 Trifolium repens）中菌根共生体的定植。将过筛的土壤分批暴露于+5°C（对照）、-10、-20、-30、-40、-50、-125°C 5 小时，并在有利于 ECM 定植的条件下将选定的植物播种到这些土壤中 10 周。在上述植物中检查了外生菌根共生体。一些外生菌根真菌的深色菌丝看起来像菌套和 Hartig 网。Kobresia filicina、K. myosuroides 和 Polygonum viviparum 就是这样的例子。本研究的结果表明，K. myosuroides 在-125°C 时表现出最佳的 ECM 根尖长度、干质量和 NH 浓度。相反，A. nitida 表现出较低的值，表明其最低耐受值。值得注意的是，T. repens 拥有最高的氮浓度（18.7±1.31mg/g），而 P. sylvestris 则在磷方面领先（3.2±0.22mg/g）。B. pendula 表现出最高的钾浓度（9.4±0.66mg/g），强调了在极端寒冷条件下特定物种对养分的吸收能力。PCA 分析表明，在+5°C、-10°C 和-20°C 温度下，NH 在土壤混合物中的参数（NH）、NO 在土壤混合物中的参数（NO）、Polygonum viviparum、Kobresia filicina、K. myosuroides、Alnus nitida、Betula pendula、Pinus sylvestris 和 Trifolium repens 物种中的磷在土壤中的参数最能准确表示。另一方面，ECM 根尖（ECM）和干质量（DM）的参数在-40°C、-50°C 和-125°C 温度下描述得最好。所有参数都对系统的可变性有很强的影响，表明 ECM 的效率。热图支持与宿主植物的 ECM 定植相关的养分呈正相关。
在低温下，根中的菌丝和孢子减少，而冷胁迫土壤中叶片的可溶性磷浓度增加。由于外生菌根的有效功能和定植，K. myosuroides 在最低温度处理下表现出最高的叶片养分浓度。
