Effects of Leaves of Some Apocynaceae Family on a Mitosis of Onion Root Cell and on Seedling Growth of Leucaena leucocephala (Lam.) de Wit.

Abstract

The effects of aqueous leaves extracts of 5 species in Apocynaceae (Allamanda cathartica L., Thevetia peruviana (Pers.) K.Schum, Catharanthus roseus (L.) G.Don, Plumeria spp. and Alstonia scholaris (L.) R. Br.) on onion root mitotic cell division and on seedling growth of Leucaena leucocephala (Lam.) de Wit. were conducted under laboratory conditions. The aqueous leaves extracts of 4 species in Thevetia peruviana (Pers.) K.Schum, Catharanthus roseus (L.) G.Don, Plumeria spp. and Alstonia scholaris (L.) R. Br. decreased the root length, mitotic cell division of the onion and mitotic index (MI). In addition, Allamanda cathartica L. leaves extracts had effect to inhibit on onion root germination. Foliar application and soil-mixing tests, the five Apocynaceae plant leaves contained allelopathic compounds, resulting in decreased number of survival, plant length and root length in Leucaena seedlings. However, the different activities of exhibition were depending on plant species, cultivar, extract concentrations, sensitivity of the test plant and soil factors