| Autor: |
Feng, Paul C C, Ryerse, Jan S, Jones, Claude R, Sammons, R Douglas |
| Zdroj: |
Pesticide Science (now called Pest Management Science); March 1999, Vol. 55 Issue: 3 p385-386, 2p |
| Abstrakt: |
Commercial formulations of glyphosate were compared for surfactant leaf damage and glyphosate uptake. The formulations (Roundup Ultra, Roundup, and Touchdown were diluted with water to 12.5 g AI litre−1 and applied as 1-μl drops to the first leaf adaxial surface. Tissues at application sites were examined by light, fluorescence and scanning electron microscopy. At 24 h after treatment, tissue necrosis was clearly visible with Ultra and Roundup, but not with Touchdown. The application sites of Ultra and Roundup, but not with Touchdown. The application sites of Ultra and Roundup demonstrated a well-demarcated zone of injury showing extensive rupturing of cell membranes in both epidermal and mesophyll cells. Studies using blank formulations without glyphosate confirmed that tissue damage was caused by the surfactant formulants. Diluted formulations (12.5 g AI litre−1) spiked with a minimum of [14C-glyphosate were applied similarly. Time-course studies showed the fastest uptake with Ultra, followed by Roundup and Touchdown. Mobilization of glyphosate away from the treated leaf was proportional to uptake. The use of a deuterium NMR method demonstrated that pretreatment of leaves with glyphosate formulations facilitated subsequent leaf loading of deuterium oxide. The extent of the latter correlated with leaf loading of glyphosate in formulations. These results indicate that the role of the surfactant is to overcome the leaf cuticle and membrane barriers to facilitate glyphosate entry into the leaf. © 1999 Society of Chemical Industry |
| Databáze: |
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