Allelopathy in Mesquite (Prosopis juliflora): A lausible Factor in Invasiveness and Dominance of the Species

Abstract

Common mesquite (Prosopis juliflora), a Fabaceae, native to South America, was first introduced into Sudan in 1917 to curb desertification. However, the plant has spread and become a weed of national importance and a threat to biodiversity. The present investigation was undertaken at the College of Agricultural Studies, Sudan University of Science and Technology to study allelopathic potentials of mesquite, and activity and persistence of the allelochemicals in soils. In all experiments lettuce (Lactuca sativa L.) was used as a test plant. Powdered mesquite parts including leaves, stems, barks and pods, showed differential effects on lettuce seed germination and seedlings growth. Germination was the least affected. Seedlings growth was affected negatively. The radicle was more sensitive to the toxins than the hypocotyl. Mesquite pods were the most suppressive followed in descending order by bark, leaves and stems. Toxins were active through soil and their persistence progressively declined with time. The results suggest that mesquite parts contain water-soluble allelochemicals and that allelopathy may contribute, considerably, to the invasive nature of the plant and its dominance.