The Effect of The Herbicide of Glyphosate (Nphosphonomethyll Glycine) On Photosynthetic Pigments And Photosynthetic Activity of Basil (Ocimum Basilicum L.) By Laser-Induced Chlorophyll Fluorescence Spectroscopy

Abstract

The aim of this study was to investigate the effect of short and long term exposure to N-(phosphonomethyl)glycine (glyphosate) on the photosynthetic activity of Ocimum basilicum L. (basil) plants. Photosynthetic pigment content, chlorophyll fluorescence, and laser-induced chlorophyll fluorescence spectra of basil plants treated for 30, 50, or 70 days with either 0,1, 2, or 3 ml/L (H2O) glyphosate were measured. The ratio of the two fluorescence intensity maxima was calculated by evaluating curve-fitted parameters. Findings revealed that after 30 days of treatment, 1 ml/l (H2O) of glyphosate stimulated, whereas 2 and 3 ml/l (H2O) of glyphosate inhibited, photosynthetic activity of basil plants. In contrast, all tested concentrations of glyphosate became inhibitory after 50 and 70 days of treatment. This study clearly showed that at high concentrations (> 1 ml/l (H2O)), glyphosate is highly toxic to basil. This finding may be helpful for determining the optimal dose of glyphosate in agricultural practices.