Compounds from the subterranean part of Johnsongrass and their allelopathic potential

Abstract

The allelopathic effects of the exotic invasive weed, Johnsongrass, on Lactuca sativa, a native plant in China, were evaluated and the phytotoxins were investigated under laboratory conditions.The crude extracts (chloroform and ethyl acetate fractions) that were obtained from the ethanol extract of the subterranean parts of Johnsongrass inhibited the germination speed and growth of the roots and shoots of the test plant. The four compounds, ethyl p-hydroxybenzoate, diosmetin, apigenin, and luteolin, were isolated from the extract of the subterranean parts of Johnsongrass first, along with three other compounds (reported previously), p-hydroxybenzaldehyde, p-hydroxybenzoic acid, and dhurrin, and they all were evaluated on L. sativa. At the concentration of <0.5 mmol L -1 , ethyl p-hydroxybenzoate, dhurrin, and the mixture of the compounds delayed the germination speed of the seeds of L. sativa at 24 h of incubation, while apigenin delayed the germination speed of the seeds of L. sativa at 72 h of incubation. Ethyl p-hydroxybenzoate demonstrated the strongest delaying effect among the phenols and a similar effect was found with apigenin among the flavonoids, wheras ethyl p-hydroxybenzoate induced a drastic inhibition of the germination at 2 mmol L -1 . In contrast, p-hydroxybenzaldehyde and luteolin had no effect on the germination at any concentration at any stage. All the substances inhibited the shoot and root growth of L. sativa at 3 mmol L -1 . Increasing the concentration increased the inhibition of the growth of L. sativa.The inhibitory activity of ethyl p-hydroxybenzoate and p-hydroxybenzaldehyde was greater than that of the other compounds.This result suggested that the isolated phytotoxins might contribute to the successful invasion by Johnsongrass.

Shift of allelochemicals from Sorghum halepense in the soil and their effects on the soil's bacterial community

“…; Liu et al . ). The phenolic compounds, p ‐hydroxybenzoic acid ( p ‐HBA) and p ‐hydroxybenzaldehyde ( p ‐HBAL), were identified as the dominant allelochemicals that are present in the leaf and rhizome extracts (Nicollier et al .…”

“…; Liu et al . ). The previous research showed that these two phytotoxins could inhibit the germination or seedling growth of several other plant species (Abdul‐Wahab & Rice ; Liu et al .…”

“…The previous research showed that these two phytotoxins could inhibit the germination or seedling growth of several other plant species (Abdul‐Wahab & Rice ; Liu et al . , Nicollier et al . ) and be directly exuded into the rhizosphere by the roots of S. halepense (Liu et al .…”

“…) and be directly exuded into the rhizosphere by the roots of S. halepense (Liu et al . ; Huang et al . ).…”

Phytotoxic activity of differents plant parts of Drimys brasiliensis miers on germination and seedling development

“…Due to the specificity of producing metabolites that are exudated directly in the environment, many compounds with relevant biological activities have been located almost exclusively in roots (OLIVEROS-BASTIDAS et al, 2009). Extracts and allelopathic phytotoxins obtained from roots have been reported to interfere in several plant development processes, including germination (SANTOS et al, 2007), root and shoot growth, normal seedling rate (LIU et al, 2011;GRISI et al, 2013), metaxylem cell growth (GATTI et al, 2010), photosynthesis, respiration and membrane transport (DAYAN et al, 2009) literature, suggesting a need for further investigation of the phytotoxic properties of roots. The results obtained for extracts of the different D. brasiliensis plant parts were compared using a joint analysis.…”