Assessment of Allelopathic Potential of Selected Legume Leaf Extracts on Seedling Growth of Raphanus sativus L.

The aim of the present investigation was to assess the allelopathic potential of 25 Bangladeshi legume plants against the seedling development of the allelopathic-sensitive plant Raphanus sativus L. Five distinct concentrations of these plant species' aqueous leaf extracts viz., 1:05, 1:10, 1:15, 1:20, and 1.25 (w/v) were employed. Every time, distilled water (with no extract) was acted as a control, and the bioassay test was repeated three times. The inhibitory actions relied on concentration and the shoot growth was less responsive to plant extracts than the root development. The shoot growth of R. sativus was less inhibited (70%) by lentil (Lens culinaris) leaf extract whilst African dhaincha (Sesbania aculeate L) at concentration of 1:05 (w/v) provided the highest inhibition (100%). At a concentration of 1:10 (w/v), the root of Krishnochura (Delonix regia), Sada koroi (Albizia procera), Radhachura (Peltophorum pterocarpum), Minjiri, (Cassia siamea), Polash (Butea monosperma), Ipilipil (Leucaena leucocephala), Tripatri shak (Desmodium triflorum), Country bean (Lablab purpureus), Black gram (Vigna mungo), Ground nut (Arachis hypogae), Yardlong bean (Vigna unguiculata) and African dhaincha (Sesbania rostrata) exhibited the highest level of inhibition (100%) while Bokful (Sesbania grandiflora), had the lowest level of inhibitory activity (87%) at the same concentration. Comparing root growth inhibition (ranged 56–81%) to shoot growth inhibition (ranged 37–77%), the aqueous leaf extracts of legume plants demonstrated a lower level of inhibition on shoot growth. Lentil (Lens culinaris) provided the lowest average inhibition (37%) on the development of R. sativus shoots and Faba bean (Vicia faba) provided the greatest average inhibition (77%). Meanwhile, Tripatri shak (Desmodium triflorum), a herb legume, provided the least average inhibition (56%) on the root development of R. sativus (56%) and Winged bean (Psophocarpus tetragonolobus) offered the greatest (81%) level of inhibition. Compared to the categories of legume species the shrubs had the most limitation on the growth of R. sativus shoots (65%), whereas herb species had the least (60%) of this effect. However, the tree species had the most root growth inhibition (70%) while the herb species had the lowest (68%). According to the findings, African dhaincha (Sesbania rostrata), followed by Soybean (Glycine max), Faba bean (Vicia faba), Blackgram (Vigna mungo), and Winged bean (Psophocarpus tetragonolobus), are prospective candidates among the examined legume plant species that have substantial allelopathic features and may be used for further allelochemical extraction and characterization.