RESUMO
Greenhouse and laboratory studies were conduct to evaluate the effect of Fluroxypyr [starane] at 200 cm[3] /feddan on one of the main crops in Egypt Zea mays and one of its associated weeds Corchorus olitorius. Single foliar treatment with the herbicide resulted in the death of the weeds 5 days after treatment, whereas the crop was non-significantly affected. Fluroxypyr treatment highly significantly decreased the fresh and dry weights of Corchorus weeds, markedly decreased the growth promoters contents [auxins, gibberellins and cytokinins], obviously increased the growth inhibitors and considerably reduced the total photosynthetic pigments by 18.3 percent as compared with the untreated Corchorus weeds. The results of the present work indicate that Fluroxypyr is an auxin-type herbicide since it stimulated the growth of Hordeum coleoptile sections at low concentrations and inhibited them at high concentrations. At 4 days after herbicide treatment, the electron micrograph showed that all the cells were disrupted and tonoplast, plasmalemma as well as chloroplast membrane were all burst. It was concluded after discussing the differential responses of the two plants, that Fluroxypyr at the recommended dose could be used to control Corchorus weed in Zea fields