Allelopathic Agents from Common Weeds
1985; American Chemical Society; Linguagem: Inglês
10.1021/bk-1985-0268.ch009
ISSN1947-5918
AutoresNikolaus H. Fischer, Leovigildo Quijano,
Tópico(s)Weed Control and Herbicide Applications
ResumoIn a search for allelopathic agents from common weeds, Amaranthus palmeri S. Wats (Palmer amaranth) and Ambrosia artemisiifolia L. (Louisiana annual ragweed) have been analysed for their organic natural products. From A. palmeri phytol, chondrillasterol, vanillin, 3-methoxy-4-hydroxynitrobenzene and 2,6-dimethoxy- benzoquinone were isolated. From the roots of Ambrosia artemisiifolia four polyacetylenes, a mixture of sesquiterpene hydrocarbons, methyl caffeate, and a mixture of β-sitosterol and stigmasterol were obtained. The germination regulation effects of ten sesquiterpene lactones, the flavonoid artemetin and the diterpene lactone, 17-acetoxyacanthoaustralide, on 12 crop and weed seeds are presented. A mechanism is proposed by which water-insoluble plant lipids (sterols etc.) may act as allelochemicals via micelle formation with long-chain fatty acids. By this process plant lipid solubility and transport in the aqueous medium are enhanced. This might suggest a reevaluation of water-insoluble plant constituents such as sterols as potential allelopathic agents.
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