Allelopathic activities of celery extract and its fractions against Corchorus olitorius, Echinochloa crusgalli and Portulaca oleracea weeds

Abstract

Aqueous extract of celery (2.5-20 g l-1, w/v) was evaluated for its phytotoxicity against three weed species, under laboratory and greenhouse conditions. Celery extract had a strong inhibitory effect on germination and seedling growth of Corchorus olitorius, Echinochloa crusgalli and Portulaca oleracea seeds. From dose response curves of tested seeds, LC50 were calculated to be in the range from 6.3 to 8.3 g l-1 for germination percent, from 7.2 to 8.0 g l-1 for shoot length and from 1.7 to 3.6 g l-1 for root length. Completely inhibition of root growth was exhibited C. olitorius and P. oleracea at 7.5 g l-1 corresponded with 15 g l-1 for E. crusgalli seed. Total phenolics in celery extract at 20 g l-1 constituted 201 mg l-1. Ten phenolic acids were identified in extract by HPLC, among of them p-coumaric acid and p-hydroxybenzoic acid were presented in high amounts. Aqueous extract was partitioning between three solvents, hexane, methylene chloride, ethyl acetate. Generally, water residue after partitioning aqueous extract with the three solvents had the most phytotoxic effect on seedling growth of target seeds. In greenhouse trial, foliar spray of aqueous extract of celery (30, 60 and 90 g l-1) and its fractions did not produce any significant effect on growth of two-weeks-old C. olitorius, or E. crusgalli or P. oleracea weeds.