ObjectivesTo study the relationship between root-rot and allelopathy of ramie, the organic compounds and allelopathic effect of rhizosphere oil water extracts were determined.
MethodsThe GC-MS was used to identify the compounds of the different polarity organic solvent extracts. The allelopathy potentials of different concentrations of rhizosphere soil water extract were bioassayed for Raphanus sativus, Brassica rapa and Arabidopsis thaliana; and QPCR was applied to determine the gene expression (RD29A, RD29B, YUC1), which was related to stress tolerance and auxin synthesis.
ResultsFifty-one compounds in four different polar organic solvent extracts were identified, including hydrocarbons and their derivatives, steroid compounds, benzoic acid and its derivatives, phenols, terpenoids, nitrogenous substances and so on, and part of them is allelophathic substance. The different concentrations of rhizosphere soil water extracts had obvious allelopathy on hypocotyl and root length of three plants to different extent. The inhibition to Brassica rapa and Arabidopsis thaliana was more significant with the increase of concentration of water extracts, less significant to Raphanus sativus. The QPCR testing results showed that the gene expression relative quantity of RD29A, RD29B and YUC1 generally decreased with the increase of the concentration of water extracts.
ConclusionsRaime rhizosphere soil is proved containing potential allelochemicals of cholest-4-ene-3,6-dione, phenol, 2,5-bis(1,1-dimethylethyl)-, diethyl phthalate, 6,6-dimethyl-1,3-heptadien-5-ol, lanosta-8,24-diene-3,22-diol. The hypocotyl and root length are mainly allelopathic effected at higher concentrations of rhizosphere soil water extracts. Therefore, we infered the allelopathy is one of the causes associated with ramie succession cropping obstacle and root-rot.
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