Tolerance of Echinochloa colona (L.) Link and Cyperus rotundus L. to propanil
F.O. Evbuomwan and O.A. Akinyemiju, Institute of Ecology and Department of Plant Science, Obafemi Awolowo University, Ile-Ife, Nigeria.
The morphological and physiological bases of the response of Ageratum conyzoides L., Oryza sativa L., Echinochloa colona (L.) Link and Cyperus rotundus L. to a post-emergence application of propanil (N-(3,4-dichlorophenyl) propanamide) were studied. Propanil retention, absorption and translocation to the roots of these species were measured using a UV/VIS spectrophotometer. The leaf area, leaf angle and stomata density were determined quantitatively. Stomata distribution and thickness of epicuticular wax were observed from photo-micrographs of transverse sections of the leaves.
Results showed that A. conyzoides retained more propanil on the leaf surface; absorbed and translocated more propanil into the plant tissues; had the thinnest epicuticular wax, highest stomata density, greatest leaf area and leaf angle as well as a wider distribution of stomates than the other species. These factors may be responsible for the susceptibility of A. conyzoides to propanil toxicity in the field. O. sativa, E. colona and C. rotundus retained little propanil on the leaf surface, absorbed less and had limited or no translocation of propanil to the stems and roots. It was inferred that these factors may be responsible for their tolerance to propanil.
Plant Protection Quarterly (1995) 10 (1) 32-34.