八宝景天花对三种杂草的化感作用及潜在化感物质鉴定

为探讨八宝景天花潜在化感物质对稗草、反枝苋、白三叶的化感作用,采用室内生物测试法,研究八宝景天花不同相萃取物对3种杂草种子萌发及幼苗生长的影响,并运用气相色谱-质谱联用技术(GC-MS)对化感活性强的萃取物进行成分分析,筛选出潜在化感物质,以相应分析纯化学试剂代替,进行化感活性鉴定。结果表明:二氯甲烷相萃取物对杂草萌发和生长有较强抑制作用,随着浓度的增加抑制作用增大,浓度在10 g·L^-1时对3种受试杂草抑制率均达100%;运用GC-MS对化感活性较强的二氯甲烷相进行化学成分分析,初步鉴定有18种化合物,从中筛选出5种潜在化感物质,其中化感综合效应最弱的为邻苯二甲酸二丁酯,对白三叶的化感综合抑制效应仅为14.1%。其他4种均有较强的抑制作用,且化感活性存在显著性差异。受试植物中白三叶最敏感,棕榈酸甲酯、安息香酸和苯酚对其化感综合抑制效应达100%。可以为八宝景天花潜在化感物质生物除草剂开发提供基础。

Allelopathic effects of Hylotelephium erythrostictum flowers on three weed species and identification of potential allelochemicals

The allelopathic effects of various extracts from Hylotelephium erythrostictum flowers on germination and early growth of seeds of the ‘weeds’ species Echinochloa crusgalli, Amaranthus retroflexus, and Trifolium repens, were studied by laboratory bioassay. Petroleum ether, methylene chloride, ethyl acetate, N-butanol and aqueous extracts were prepared. The dichloromethane extract had a strong inhibitory effect on weed germination and growth, and the inhibitory effect increased with increasing concentration. The inhibition effect on the three tested weed species reached 100% at an extract test concentration of 10 g·L-1. The methylene chloride extract also displayed strong allelopathic activity. GC-MS was used to analyze the chemical constituents of these extracts, and 18 compounds were initially identified, from which 5 potential allelopathic were screened out: dibutyl phthalate, methyl hexadecanoate, benzenemethonic acid, octadecanoic acid methyl ester, and phenol. For these five compounds, samples of analytical purity were obtained and used to test for allelochemical activity. The effect of dibutyl phthalate was weak, with the allelopathic inhibitory effect on T. repens germination only 14.1%, while the other four had strong inhibitory effects, and there were significant differences in allelopathic activities. T. repens was the most sensitive among the tested species, and methyl hexadecanoate, benzenemethonic acid and phenol had an inhibitory effect of 100% in this species. This study identifies compounds with allelochemical activity that might potentially be used as bioherbicides for H. erythrostictum.