Allelochemicals in the Rhizosphere Soil of Euphorbia himalayensis

Abstract

Weed infestation has been known to cause considerable reductions in crop yields, thereby hindering sustainable agriculture. Many plants in genus Euphorbia affect neighboring plants and other organisms by releasing chemicals into the environment. In view of the serious threat of weeds to agriculture, the allelochemicals of Euphorbia himalayensis and their allelopathic effects were investigated. The extract of root exudates from rhizosphere soil exhibited allelopathic activities against crops (wheat, rape, and lettuce) and grasses (Poa annua, Festuca rubra, and red clover). Bioassay-guided fractionation and isolation from the root extract of E. himalayensis led to the characterization of two ellagic acid derivatives and a jatrophane diterpene, which observably showed phytotoxic activities against lettuce, Festuca arundinacea, and F. rubra. They were further confirmed by ultra-performance liquid chromatography-tandem mass spectrometry to have concentrations of 3.6, 3.8, and 8.99 nmol/g in the rhizospere soil, respectively. Bioassay indicated that the combination of the allelochemicals could be selective plant growth regulator in agriculture.

Screening of Allelochemicals in Miscanthus sacchariflorus Extracts and Assessment of Their Effects on Germination and Seedling Growth of Common Weeds

“…These compounds accumulate in the soil through plant residual decomposition, root exudation, and shoot leaching processes [ 40 , 41 , 42 ]. Various studies have reported the isolation of single allelopathic compounds and their application for the development of herbicides [ 43 , 44 , 45 , 46 ]. Moreover, a number of allelochemicals from potentially allelopathic plants species have already been isolated and have proven to successfully inhibit weed germination and growth [ 47 ], making them environmentally friendly compared to chemical herbicides [ 48 ].…”

Root-mediated allelopathic interference of bhringraj (Eclipta alba L.) Hassk. on peanut (Arachis hypogaea) and mung bean (Vigna radiata)

“…As reported by Turk and Tawaha (2003), phenolic acids are among the main category of allelochemicals in nature. These phenolic compounds can inhibit root elongation and cell division in plants, and can cause changes to the cell ultrastructure, thus interfering with the normal growth and development of the whole plant (Liu et al, 2014). Based on the results, the study concludes that E. alba interferes with A. hypogaea and V. radiata by releasing water-soluble phenolics and allelopathy is operative in the community dominated by E. alba and may even provide an advantage to the weed.…”

Phytotoxic Diterpenoids from Plants and Microorganisms

“…Bo Qin et al. also isolated esulone A ( 217 ) from the roots of Euphorbia himalayensis . Its phytotoxic effects on lettuce, F. arundinacea , and Festuca rubra seedlings were tested, whose growth was inhibited in a dose‐dependent relationship.…”

“…Bo Qin et al also isolated esulone A (217) from the roots of Euphorbia himalayensis. [58] Its phytotoxic effects on lettuce, F. arundinacea, and Festuca rubra seedlings were tested, whose growth was inhibited in a dose-dependent relationship. In addition, the inhibitory effect of esulone A on F. arundinacea was stronger than on F. rubra, especially at low concentrations.…”