Adaptation mechanism of plants to the stressful environments of Danxia Landscape mediated by mycorrhizal fungi

<p indent="0mm">The mutualistic symbioses between plants and mycorrhizal fungi are widespread in forest communities, playing crucial roles in regulating plant interspecific competition, community structure, succession, as well as ecosystem function and stability. However, previous studies primarily focused on how mycorrhizal fungi regulate the niche differentiation among plants with different mycorrhizal types and the plant-soil feedback effects, while overlooking the dynamic changes in host-mycorrhizal interactions under different habitat conditions. Based on the unique ecological effects and soil stress conditions on the hilltops of Mt. Danxia in Guangdong, this study systematically analyzed the soil physical and chemical properties, the mycorrhizal colonization rates of host roots, the morphological characteristics and diversity of fruiting bodies, to compare the differences in the intensity of plant-mycorrhizal interactions between the mountain summit and valley among individuals of the same plant species. We found that the forest soil on summit was significantly more barren and droughty than the valley habitat. The root colonization rates of mycorrhizal fungi in plant individuals distributed in the summit were significantly higher than that in the valley, while the individual sizes of mycorrhizal sporocarps on the summit were generally smaller than those of the same species in the valley. In this forest, both of the two main mycorrhizal types of tree species exhibited higher dependencies on mycorrhizal symbiosis in the summit than in the valley, indicating enhanced ability to acquire soil nutrients and water, ultimately improved fitness for host plants under the stressful conditions on the hilltops. This study reveals that tree species adapt to stressful habitats by dynamically adjusting their interactions with mycorrhizal fungi, providing a new perspective on plant adaptation strategies and biodiversity maintenance mechanisms under environmental heterogeneity.