Role of ectomycorrhizal colonization in enhancement of nutrients for survival of plants collected from mountainous cold stress areas
Résumé
Background: 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.
Results: 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 NH4 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., NH4 in soil mix (NH4), NO3
in soil mix (NO3), 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.
Conclusion: 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.