Allelopathic effects of aqueous and organic fractions of Euphorbia dracunculoides Lam. on germination and seedling growth of chickpea and wheat Efectos alelopáticos de fracciones acuosas y orgánicas de Euphorbia dracunculoides Lam. sobre la germinación y crecimiento de plántulas de garbanzo y trigo

Identification of weed species with allelopathic potential and characterization of their adverse effects against associated crops is required for better understanding of weed-crop interactions. Phytotoxic activity of Euphorbia dracunculoides Lam. on germination and seedling growth of chickpea (Cicer arietinum L.) and wheat (Triticum aestivum L.) was investigated under controlled conditions. Two separate studies were done with each of four organic solvent fractions (n-hexane, chloroform, ethylacetate, 1-butanol) and crude aqueous (1:10 and 1:20) whole plant fractions of E. dracunculoides using distilled water and 0.05% (v/v) dimethyl sulfoxide (DMSO) as control. Different aqueous and organic fractions of E. dracunculoides had a significant bearing on germination attributes and seedling growth that varied among tested species. The final germination percentage of wheat remained unaffected; nevertheless, root and shoot elongation and biomass accumulation in these parts were significantly retarded. Aqueous fractions appeared more phytotoxic than organic fractions and suppressed chickpea germination by 35-53%. These aqueous fractions also reduced root (64-75% and 33-34%) and shoot (18-62% and 21%) length and root (32-33% and 42-46%) and shoot (7-32% and 80-84%) dry weight of wheat and chickpea, respectively. Among organic fractions, n-hexane was more suppressive to test species. Chromatographic analysis revealed the presence of four phytotoxins, furoic, p-coumaric, syringic, and caffeic acids, in aqueous whole plant (1:10) fractions. This study determined the phytotoxic allelopathic activity of E. dracunculoides against wheat and chickpea. Se requiere la identificación de especies de malezas con potencial alelopático y la caracterización de sus efectos adversos en contra de los cultivos asociados para una mejor comprensión de las interacciones cultivos-malezas. Se investigó la actividad fitotóxica de Euphorbia dracunculoides Lam. en la germinación y crecimiento de plántulas de garbanzo (Cicer arietinum L.) y trigo (Triticum aestivum L.) bajo condiciones controladas. Dos estudios separados se realizaron con cada una de las cuatro fracciones de disolventes orgánicos (n-hexano, cloroformo, acetato de etilo, 1-butanol) y extracto acuoso (1:10 y 1:20) de fracciones enteras de plantas de E. dracunculoides usando agua destilada y 0,05% (v/v) dimetil sulfóxido (DMSO) como control. Diferentes fracciones acuosas y orgánicas de E. dracunculoides tuvieron una incidencia significativa en los atributos de germinación y crecimiento de las plántulas de las especies evaluadas.