PHYTOTOXIC EFFECTS OF CITRULLUS COLOC YNTHIS (L.) SCHRAD ON CERTAIN CROP PLANTS

Abstract

Effect oI Citrullus coloc ynthis on tire germination and seedling gtcwth of five crop species was invcstignted. Aqueous extra ct of shoot or Ctru//us af1'ected ger rnination and seedling growth in the order: Laetuca sativa, Sorghum bicalor. Brrssica rapa, Pennisetum americanum, Medicago siitiva. Root extract i.riJfi bited the gerrrii nation of only three species in the order: Pennisetum amerioanum, Sorghum bicolor, Grassier r‹ipa but was sSimulator y to Medicugo native •und Lartuca sativ‹i. Both shoot and root extracts affected root growth to a greater extent than the shoot growth. Decaying shoot and root of‘ 6'ifruJ/tzs were laigkl y pliytoto xic to gerrnii'iati on and seedling giowtli of S. bicolor. Artificial rain-drip collected from Citrullus leaves arrested seedling growth of L. sativa and S. bitolor. Coleoptile bioassay of the ether cxtiact indicated some inhibitors in both shoot and root extract and paper chromatography revealed the presence of cnffeic and vanillic aeids. Possible iniplica tions of the results are discussed.