Abstract

COSTA, N.V.; MARTINS, D.; RODELLA, R.A.  and  RODRIGUES-COSTA, A.C.P.. Anatomical leaf changes in Eichhornia crassipes due to herbicides application. Planta daninha [online]. 2011, vol.29, n.1, pp. 17-23. ISSN 0100-8358.  http://dx.doi.org/10.1590/S0100-83582011000100003.

The aim of this work was to evaluate the efficacy of 2,4-D, diquat and glyphosate control and the leaf blade anatomic changes provided by these herbicides in Eichhornia crassipes, collected in the reservoirs of the CESP complex. The plants were grown in reservoirs containing water under field conditions. When these plants reached the stage of full vegetative development, they were sprayed with solutions of diquat at 400 g a.i. ha^-1 , 2,4-D at 1.340 g a.e. ha^-1 and glyphosate at 4.320 g a.e. ha 1 in combination with Silwet L-77 at 0.01% v v^-1.A control without herbicide was also used .Evaluations were carried out of the control and of the following anatomical quantitative characteristics of the vein and intervein central regions of the leaf blade: percentage of the adaxial and abaxial epidermis, percentage of the endoderm, percentage of vascular bundle, percentage of the aerenchyma lacuna, percentage of parenchyma and leaf thickness (µm). According to the results, the main anatomical quantitative characters of the vein and intervein central regions of the leaf blade that changed after herbicide application were: percentage of the adaxial epidermis, percentage of the endoderm, and leaf thickness. Diquat and 2,4-D promoted changes in the anatomical quantitative characters of the vein and intervein central regions of the leaf blade in E. crassipes. Only glyphosate provided 100% of E. crassipes control at 22 days after application, compared with the control without herbicide.

Keywords : leaf anatomy; aquatic plant; weed; chemical control.