Allelopathic activity of the root exudate of <I>Jatropha curcas</I> L. on seedlings of <I>Brassica napus</I> L., <I>Glycine max</I> L., <I>Zea mays </I>L. and <I>Helianthus annuus</I> L.

Abstract

The aim was to evaluate the effect of root exudate of J. curcas on germination and early growth of the B. napus, G. max, Z. mays and H. annuus seedlings. J. curcas seeds (15 and five, respectively, by repetition, for eight days, to obtain the root exudate. After this period, 50 G. max, H. annuus and Z. mays seeds were put to germinate by seven days in rolls of paper. Twenty five B. napus seeds were put to germinate in Petri dishes by eight days. Four replicates of experiments were performed in germination chamber with controlled temperature and photoperiod, with experimental design completely randomized. The parameters evaluated were germination percentage, average germination time, average speed of germination and length of roots. After statistical analysis (Tukey 5% probability) was concluded that J. curcas exerted allelopathic effect diverse on the species studied, showing positive effect on G. max seedlings (time and speed averages of germination, length of roots) and negative effects on time and speed averages of germination of H. annuus seedling and the length of roots of B. napus seedlings.