An M, Pratley J E, Haig T
Environmental and Analytical Laboratories, Charles Sturt University, Wagga Wagga, NSW 2678, Australia.
J Chem Ecol. 2001 Feb;27(2):383-94. doi: 10.1023/a:1005640708047.
Twenty compounds identified in vulpia (Vulpia myuros) residues as allelochemicals were individually and collectively tested for biological activity. Each exhibited characteristic allelochemical behavior toward the test plant, i.e., inhibition at high concentrations and stimulation or no effect at low concentrations, but individual activities varied. Allelopathins present in large quantities, such as syringic, vanillic, and succinic acids, possessed low activity, while those present in small quantities, such as catechol and hydrocinnamic acid, possessed strong inhibitory activity. The concept of a phytotoxic strength index was developed for quantifying the biological properties of each individual allelopathin in a concise, comprehensive, and meaningful format. The individual contribution of each allelopathin, assessed by comparing the phytotoxic strength index to the overall toxicity of vulpia residues, was variable according to structure and was influenced by its relative proportion in the residue. The majority of compounds possessed low or medium biological activity and contributed most of the vulpia phytotoxicity, while compounds with high biological activity were in the minority and only present at low concentration. Artificial mixtures of these pure allelochemicals also produced phytotoxicity. There were additive/synergistic effects evident in the properties of these mixtures. One such mixture, formulated from allelochemicals found in the same proportions as occur in vulpia extract, produced stronger activity than another formulated from the same set of compounds but in equal proportions. These results suggest that the exploration of the relative composition of a cluster of allelopathins may be more important than simply focusing on the identification of one or two compounds with strong biological activity and that synergism is fundamental to the understanding of allelopathy.
在鼠茅（Vulpia myuros）残体中鉴定出的20种作为化感物质的化合物，分别和共同进行了生物活性测试。每种化合物对受试植物都表现出典型的化感物质行为，即高浓度时抑制，低浓度时刺激或无影响，但个体活性有所不同。大量存在的化感物质，如丁香酸、香草酸和琥珀酸，活性较低，而少量存在的，如儿茶酚和氢化肉桂酸，具有很强的抑制活性。为了以简洁、全面且有意义的形式量化每种化感物质的生物学特性，提出了植物毒性强度指数的概念。通过将植物毒性强度指数与鼠茅残体的总体毒性进行比较来评估每种化感物质的个体贡献，其因结构而异，并受其在残体中的相对比例影响。大多数化合物具有低或中等生物活性，对鼠茅的植物毒性贡献最大，而具有高生物活性的化合物占少数且仅以低浓度存在。这些纯化感物质的人工混合物也产生了植物毒性。这些混合物的性质存在明显的加和/协同效应。一种由与鼠茅提取物中相同比例的化感物质配制而成的混合物，比另一种由相同一组化合物但等比例配制而成的混合物具有更强的活性。这些结果表明，探索一组化感物质的相对组成可能比单纯关注鉴定一两种具有强生物活性的化合物更为重要，并且协同作用对于理解化感作用至关重要。
