Allelopathic Potentials of Medicinal Plant, Vinca rosea L.

Allelopathy offers potential for weed control through the production and release of allelochemicals from leaves, flowers, seeds, stems and roots.  In this research, allelopathy potentials of ethanolic and aqueous extracts of Vinca rosea L. leaves were evaluated. Three extract concentrations, including 2.5, 5 and 10% (w/v) of both aqueous and ethanolic were prepared from a 10% w/v stock solution in a completely randomized design with three replications. Distilled water was used as negative control. The inhibitory effects of V. rosea extracts on seed germination, hypocotyl) the part of the stem of an embryo plant) and radicle (the part of a plant embryo that develops into the primary root) length and seedlings growth of five plants were tested. The plants were cucumber (Cucumis sativus), redroot amaranth (Amaranthus retroflexus), garden cress (Lepidium sativum), scale cereal (Secale montanum) and desphia herb (Descurainia sophia). Results showed that the 10% aqueous extracts on the A. retroflexus, D. sophia and L. sativum and 10% ethanolic extracts on the five tested plants inhibited seed germination completely. The 10% aqueous extract inhibited the hypocotyls lenght of L. sativum, A. retroflexus and D. sophia completely. The 10% aqueous and ethanolic extract of V. rosea inhibited the radicle lenght of L. sativum, A. retroflexus and D. sophia completely. The inhibitory effects of the V. rosea extract may be related to the presence of allelochemicals, including alkaloids, flavonoids and phenolic acids. The use of allelopathic materials into agricultural management may reduce the use of pesticides and lessen environmental side effects.