International Journal of Molecular Ecology and Conservation, 2025, Vol.15, No.5, 240-248 http://ecoevopublisher.com/index.php/ijmec 24 0 Review and Progress Open Access Survival and Suppression: Black Walnut’s Allelopathic Strategies Chuchu Liu 1 , Zhonggang Li 2 1 Cuixi Academy of Biotechnology, Zhuji, 311900, Zhejiang, China 2 Hainan Institute of Tropical Agricultural Resources, Sanya, 572025, Hainan, China Corresponding email: chuchu.liu@cuixi.org International Journal of Molecular Ecology and Conservation, 2025, Vol.15, No.5 doi: 10.5376/ijmec.2025.15.0024 Received: 16 Aug., 2025 Accepted: 28 Sep., 2025 Published: 10 Oct., 2025 Copyright © 2025 Liu and Li, This is an open access article published under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Preferred citation for this article: Liu C.C., and Li Z.G., 2025, Survival and suppression: black walnut’s allelopathic strategies, International Journal of Molecular Ecology and Conservation, 15(5): 240-248 (doi: 10.5376/ijmec.2025.15.0024) Abstract From the perspective of chemosensory ecology, this study systematically explored the sources and types of chemosensory substances in black walnut trees, the mechanism of action of juglanone and its target plant responses, and further analyzed its ecological functions in resource competition, community dynamics and symbiotic relationships. At the same time, the dual effects of the sensitization effect of black walnut in forestry and agricultural management were also discussed, as well as its adaptive significance in the context of global change. Research has found that by releasing sensitizing substances into the environment, especially the key compound Juglone, black walnuts can inhibit the germination and growth of surrounding plants, thus gaining an advantage in resource competition. This kind of "chemical war" not only affects the physiological metabolism and community structure of neighboring species, but also has a profound impact on community diversity and ecological balance. This study also proposed that in the future, efforts should be made to enhance the analysis of molecular target mechanisms, dynamic modeling of soil sensitizing substances, and the design of complex ecosystems. From the perspective of chemosensory ecology, exploring how black walnut achieves "survival and suppression" through chemosensory substances is of great significance for understanding the dynamics of forest communities and developing natural management methods in agriculture and forestry. Keywords Black walnut; Chemosensory effect; Walnut ketone; Chemosensory substances; Ecological competition 1 Introduction The black walnut (Juglans nigra) is native to North America and is a broad-leaved tree species with both economic and ecological value (Nicolescu et al., 2020). Its wood is hard and beautiful, and is widely used in the manufacturing of high-end furniture and flooring. Nuts are rich in oil and protein and are edible and used in the food processing industry. Meanwhile, the black walnut tree has a majestic posture and ornamental value. Its bark, leaves and green peels are used in traditional medicine to treat diseases (Nicolescu et al., 2020; Athaillah et al., 2024). For instance, the active substances contained in the green peel of black walnut are used in folk remedies such as antibacterial, deworming and pain relief (Jahanban-Esfahlan et al., 2019; Liu et al., 2022). In the ecosystem, the most prominent feature of black walnut is its strong inhibitory effect on adjacent plants: there are historical records as early as before the Common era that it is difficult for grass and trees to grow under walnut trees. This phenomenon was scientifically confirmed in the 19th century to be caused by the release of specific chemical substances from walnut trees (Liu et al., 2022). Black walnut produces a typical chemosensitic substance - juglone, which can inhibit the germination and growth of other plants in the soil (Nicolescu et al., 2020; Medic et al., 2021b). Allelopathic action, as one of the important strategies for competition and balance among plants, plays a crucial role in maintaining the competitive edge of black walnuts in the ecosystem. It not only won space and resources for black walnuts, but also to some extent changed the diversity and structure of the community, and might even affect the relationship between the animals and plants that coexist with them. The "black walnut effect" has become a classic example in the study of chemosensory effects. Studying the strategy of black walnut competing with surrounding plants through "chemical warfare" not only helps to reveal the interspecific relationships and species succession mechanisms of forest communities, but also contributes to the development of weed control measures based on plant natural products, serving ecological management in agriculture and forestry (Islam and Widhalm, 2020; Dolianitis et al., 2025).
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