International Journal of Molecular Ecology and Conservation, 2025, Vol.15, No.5, 240-248 http://ecoevopublisher.com/index.php/ijmec 24 6 rainy climate, juglanone in the soil is more prone to leaching and dilution, and its continuous inhibitory effect on vegetation may be weakened. In dry seasons or poorly drained soil, walnut ketone is more likely to accumulate, thereby enhancing the sensory effect (Choudhary et al., 2023). Similarly, it can be speculated that under drought stress, black walnuts may secrete more juglanone to reduce competition, or due to water shortage, juglanone may act more intensively on local soil areas, thus exerting more obvious suppression on adjacent plants. On the contrary, under conditions of high precipitation and irrigation, the concentration of juglanone is diluted and degraded more quickly, and its "medicinal power" will be weakened (Islam and Widhalm, 2020). Temperature is an important factor in the sensory effects of black walnut. When it gets warmer, trees often produce more secondary metabolites such as walnutone. But higher heat can also make these compounds break down faster in the soil (Liu et al., 2022). This means climate warming has two sides. It can boost the release of sensitive substances inside the tree, but it can also shorten how long they stay in the soil because soil microbes become more active. The rise of CO₂ in the air also matters. Extra CO₂ usually speeds up carbon use in plants and pushes secondary metabolism. Studies show that under high CO₂, the level of some sensitizing substances goes up, which may increase their inhibitory effect. Even though there is no full study yet on how walnut ketone acts under different climate conditions, current evidence suggests that global change will shape the adaptability of black walnut’s chemical strategy. In dry areas, it may gain more strength because of its higher advantage. In wetter regions, or where soil microbes are active, its effect may become weaker (Islam and Widhalm, 2020; Kaur et al., 2024). 6.2 The Potential and Limitations of chemosensory strategies in combating Invasive plants Whether the sensitizing effect of black walnut can play a "biological control" role in the global plant invasion problem is an aspect worthy of attention. Theoretically, broad-spectrum and long-lasting chemogenic substances like walnut ketone can inhibit many invasive alien plants and provide a certain protective barrier for native species (Ferus et al., 2020). For example, when introducing black walnut in some parts of Europe, studies have observed that the numbers of several invasive weeds under its forest (such as Solidago canadensis, Delphinium, etc.) are relatively small, which is speculated to be related to the inhibitory effect of juglandone (Nicolescu et al., 2020). In particular, the strong inhibitory effect of black walnut on the seedlings of Ailanthus altissima (a globally notorious invasive tree species) has aroused people's interest in using walnut trees to inhibit the spread of Ailanthus altissima (Ferus et al., 2020). However, the transformation-based strategy also has clear limits in resisting invasive plants. Some species are not sensitive to juglanone, and some even show strong tolerance. Garlic grass is a typical case. This invasive crucifer can still thrive under black walnut forests and shows high resistance to juglanone. It may avoid its toxicity through its own metabolic system or by relying on symbiotic microbes. Invasive plants also spread fast and reproduce well. Even if many seedlings are suppressed, enough may survive and expand into the community edge. In addition, global changes may give some invasive plants stronger adaptability, further reducing the effect of the black walnut chemical barrier (Scavo and Mauromicale, 2021; Khamare et al., 2022; Murthy et al., 2025). 7 Concluding Remarks Black walnuts rely on juglanone and related compounds to build a survival strategy of “inhibition and persistence.” On one hand, they suppress surrounding plants and secure an advantage in resource competition. On the other, the strength of this effect shifts with environmental context, producing both gains and potential risks. Thoughtful management is therefore required. In natural ecosystems, allelopathy is seen as a driver of black walnut dominance during community succession. In agriculture and forestry, it provides insights for weed control and ecological planting. Plant-derived herbicides based on juglanone, or intercropping systems that reduce pesticide use, may also support sustainable production. Several obstacles remain before broader and safer application can be achieved. Juglanone-based products require greater stability, and their impacts on non-target species must be clarified. The adaptive strategies of invasive plants present further complications. Future research directions are clear. First, molecular targets of juglanone and
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