Bidens pilosa L. exhibits high sensitivity to coumarin in comparison with three other weed species.
Nine natural plant compounds were screened for phytotoxicity to Bidens pilosa L. a troublesome weed in field and plantation crops. The sensitivity of three other weed species to coumarin, the most active identified compound, was also evaluated. Coumarin, at a concentration of 500 microM, had little effect on germination and growth of Senna obtusifolia L., Euphorbia heterophylla L., and Ipomoea grandifolia L. when compared with its effects on B. pilosa L. In a concentration range of 10-100 microM, coumarin caused a dose-dependent inhibition of germination and growth of B. pilosa L. The measurements of some parameters of energy metabolism revealed that coumarin-treated root tissues exhibited characteristics of seedlings in an earlier stage of growth, including higher respiratory activity and higher activities of alcohol dehydrogenase and lipoxygenase. These results suggest that coumarin inhibition of germination and growth of B. pilosa L. was not a consequence of an impairment of energy metabolism. Rather, it seems to act as a cytostatic agent, retarding germination. At concentrations above 50 microM, coumarin increased lipoxygenase activity and the level of conjugated dienes of root extracts, suggesting that it may induce oxidative stress in seedling roots.
Pergo
Erica Marusa
EM
Laboratory of Biological Oxidations, Department of Biochemistry, University of Maringá, 87020900 Maringá, Brazil.
Abrahim
Denise
D
Soares da Silva
Patrícia Cristina
PC
Kern
Kátia Aparecida
KA
Da Silva
Lucas Jonatas
LJ
Voll
Elemar
E
Ishii-Iwamoto
Emy Luiza
EL
D031176:Bidens / Q000187:drug effects* / Q000502:physiology; D003374:Coumarins / Q000494:pharmacology*; D018525:Germination; D013045:Species Specificity
D003374:Coumarins; C030123:coumarin