Allelopathic Potentials of Cuscuta campestris Yuncker Extracts on Germination and Growth of Radish (Raphanus sativus L.) and Lettuce (Lactuca sativa L.)

Abstract

Cuscuta campestris Yuncker, commonly known as Golden dodder is an annual problematic parasitic weed in abandoned and derelict areas in Malaysia. The weed is leafless plant, glabrous, yellow-white in colour, with haustoria, sucker-like attachments to the aerial parts of a wide range of host plants. This study was instituted to assess the allelopathic potentials of C. campestris on lettuce and radish as test plants. Three types of treatment using aqueous extract of fresh (fc), and dried s (dc) and ethanol extract of dried C. campestris (ec) were assayed for their allelopathic effects on radish (Raphanus sativus) and lettuce (Lactuca sativa) seeds. These extracts reduced seed germination, root and shoot lengths of both radish and lettuce. The roots of radish were more sensitive vis-à-vis the shoots when exposed to fc, while shoots were more sensitive than roots when exposed to dc. Dose-mediated differences in shoot and root lengths of radish were registered when treated with ec. The roots of lettuce were more sensitive compared with the shoots when exposed to ec, while no measurable effect was observed when roots and shoots of lettuce were exposed to fc and dc. The results demonstrated the allelopathic effects of dodder on the tested host plants. The potentials of these extracts and their chemical constituents as bioactive ingredients for new herbicides are implied.

Allelopathic tolerance of alfalfa (Medicago sativa L.) varieties to dodder (Cuscuta epithymum L.)

“…Seed germination was mostly unaffected by the tested fresh weed extract of C. epithymum only in the M. sativa variety "Multifoliolate", while nonsignificant stimulating effects were only found at the highest concentrations (50 and 100 g/l -1 ). Similar results were reported by Othman et al (2012), showing that fresh plant extracts of C. campestris did not reduce seed germination of radish (R. sativus).…”

“…Allelopathic tolerance was detected in the varieties "Victoria", "Prista 5" and "Multifoliolate". Similar results in radish (R. sativus) and lettuce (L. sativa) were reported by Othman et al (2012). They found that the species of test plants and their varieties had different levels of susceptibility to allelopathic effects of plant extracts (from fresh or dry biomass) and that they depended on the applied concentrations.…”

“…Allelochemicals are known to be toxic and have lethal effect on seeds at higher concentrations, whereas their lower concentrations inhibit seed germination of test plants (Macías et al, 2007;Yu et al, 2011;Othman et al, 2012;Baličević et al, 2014).…”

Allelopathic Activity of Extracts from Different Brazilian Peanut (Arachis hypogaea L.) Cultivars on Lettuce (Lactuca sativa) and Weed Plants

“…This value was almost three times higher than that observed with extracts of A . hypogaea seeds for the same species and at the a similar concentration (less than 2.00 cm) [15]. In the evaluation of coffee fruit extracts (Coffea arabica) , the concentration required for the growth inhibition of hypocotyls and rootlets of L .…”

Allelopathic potential of the invasive species Aster lanceolatus Willd.

“…Fifty grams of fresh rhizomes, stems and leaves were cut into small pieces and oven-dried at 40 o C for 48 hours (17). The dried tissue was milled to a powder and added to 250 ml of distilled water to soak for 24 hours.…”