Abstract: Allelopathy and chemical communication among plants are the chemical response strategies of plants to coexisting intra- and inter-specific plants. Such intra- and inter-specific chemical interactions of plants actively affect their survival and reproduction, population and community dynamics, as well as ecosystem productivity. Allelopathy and chemical communication are respectively mediated by allelochemicals and signaling chemicals produced and released by plants, while signaling chemicals-mediated recognition and communication may activate the corresponding mechanism of allelopathy among plants. Recent studies have found the chemical recognition among relatives within the same plant species, which can coordinate root behavior, flowering, reproduction, and inter-specific allelopathy through conspecific cooperation caused by kin recognition. Although considerable progress has been made in allelopathy and chemical communication among plants, their role in driving temporal and spatial variations of individuals, populations, communities, and ecosystems, are far more complex than expected, and hold many worth exploring questions. Accordingly, we elaborated thoughts in allelopathy and chemical communication from five aspects: plant competition and allelopathy and kin recognition, allelopathy and neighbor identity recognition, positive and negative interactions and their utilization strategies, root signal-mediated below- and above-ground interactions, and allelochemicals and signaling chemicals as well as their dynamic capture and identification. The aim of this review was to promote peers to re-examine the chemical interactions among plant species and their effects on plant communities and ecosystems from a new insight and perspective.

Key words: plant chemical interaction, neighbor identity, kin recognition, allelochemical, signaling chemical, belowground and aboveground interaction.