Phenolic changes and allelopathic potential in different concentrations of methanolic and ethanolic extracts from root and shoot of Rumex turcomanicus Czerep. on lettuce (Lactuca sativa L.) seedling

To investigate the allelopathic potential and its relation with phenolic changesin different concentrations of methanolic and ethanolic extracts from root and leaf of Rumex turcomanicus Czerep.on seed germination and seedling growth of lettuce (Lactuca sativa L.), a factorial experiment based on completely randomized design was conducted at the Faculty of Agriculture, Ferdowsi University of Mashhad, Iran, in 2013. Treatments included different organs of Rumex turcomanicus Czerep (root and leaf), two extraction solvents (methanol and ethanol), and six concentrations of extract (0, 31.25, 62.5, 125, 250 and 500 ppm), whose effects were studied on seed germination and seedling growth of lettuce. The extracts were placed in petri dishes in three replicates and 25 seeds (lettuce) per replicate. Phenolic content was measured in each extract. The results showed higher inhibition in methanoilc extracts as compared with ethanolic extracts and higher inhibition in root extract as compared with leaf extracts on seed germination and most of seedling the growth traits. Among different concentrations, maximum and minimum inhibition were observed in 500 and 0 ppm of extracts, respectively. Phenolic content was greater in methanolic as compared with ethanoilc extracts and was higher in root extracts as compared with leaf extracts. In addition, phenolic content was increased with increasing of extract concentration. A positive and significant correlation was observed between phenolic content and allelopathic potential.