Effect of Water Extract Originated from Different Part of Russian Knapweed (Acroptilon repens L.) on Growth of Purslane (Portulaca oleracea L.)

To evaluate probable allelopathic effect of water extract originated from different parts of russian knapweed (Acroptilon repens L.) on growth of purslane (Portulaca oleracea L.), a factorial experiment was conducted based on randomized complete block design with three replications at greenhouse condition in 2011. Treatments were water extract concentrations (0, 5, 10, 15 and 20 percent) obtained from different part of russian knapweed (aerial part, flower and root). Results showed the significant effect of extract type on seedling length, and extract concentration on shoot length, root length and seedling length. Interaction effect between extract type and concentration on the ratio of root/shoot length, seedling fresh weight, seedling dry weight and germination percentage was significant, too. Means comparison indicated that the longest root (3.55 cm), shoot (4.65 cm) and seedling (8.20 cm) were obtained from control treatment, reducing with higher concentration of extract. The longest shoot (6.95 cm) belonged to extract originated from russian knapweed flowers. The highest ratio of root/shoot length (0.73), seedling fresh weight (0.61g) and seedling dry weight (0.044 g) belonged to control treatment. In general, increasing of extract concentration caused in reduction of germination and seedling traits. Meanwhile, extracts of aerial part had more sever reducing effect than root and flower extracts.