International Journal of Molecular Ecology and Conservation, 2025, Vol.15, No.5, 240-248 http://ecoevopublisher.com/index.php/ijmec 24 4 Figure 2 Allelochemical-mediated below-ground interactions and plant–soil feedback (Adopted from Xu et al., 2023) 4.3 Potential conflicts and coordination with symbiotic relationships Chemicals released by black walnuts can suppress the growth of nearby plants, yet at the same time may interfere with their own symbiotic partners. This tension often results in conflict or requires delicate balance. Compounds such as juglanone not only hinder competitors but also influence beneficial soil microbes, including mycorrhizal fungi and nitrogen-fixing bacteria. As a result, the close associations between walnut roots and these organisms can be weakened. In walnut stands, shifts in AM fungal communities are common: sensitive groups decline, while tolerant ones gradually dominate, reflecting microbial adaptation under juglanone stress (Jose, 2002). Intercropping experiments, however, indicate that carefully chosen plant combinations can mitigate or even offset these allelopathic effects, thereby fostering more stable symbioses. In southwest China, for instance, tea trees have been cultivated alongside walnuts. The results showed improved soil nutrient status, greater microbial diversity, and tea yields that were only minimally affected (Bai et al., 2022). Additional studies suggest that the roots of certain companion plants can secrete compounds accelerating juglanone degradation, reducing its accumulation and easing its harmful influence on the broader system. 5 Application Perspective: The Double-Edged Sword Role of Black Walnut in Forestry and Agriculture 5.1 Weed control potential and natural weeding strategies The strong chemical sensation effect of black walnut provides a new idea for the development of natural herbicides. Research has found that juglanone, as a natural substance derived from plants, has a significant inhibitory effect on algicolor in various weeds, and thus is regarded as a potential candidate for bioherbicides (Ferus et al., 2020; Islam and Widhalm, 2020). The experimental results show that juglanone can not only significantly prevent the seed germination and seedling growth of common weeds in the field, but also has relatively low toxicity to certain crops (Bishop et al., 2024). In forestry applications, black walnut reduces undergrowth weeds and competing trees by virtue of its own allelopathic effect, thereby lowering the management and tending costs of young forests (Ferus et al., 2020). In
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