Browsing by Author "Pino, I"

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    Differential phytotoxicity of glyphosate in maize seedlings following applications to roots or shoot
    (WILEY, 2005) Alister, C; Kogan, M; Pino, I
    The transport and differential phytotoxicity of glyphosate was investigated in maize seedlings following application of the herbicide to either roots or shoots. One-leaf maize seedlings (Zea mays L.) were maintained in graduated cylinders (250 mL) containing nutrient solution. Half of the test plants were placed in cylinders (100 mL) containing different C-14-glyphosate concentrations; the remainder received foliar appliation of C-14-glyphosate. After 26 It, the roots and the treated leaves were washed with distilled water, and the plants placed again in cylinders (250 mL) containing fresh nutrient solution for 5 days. Plants were weighed, and split into root, seed, cotyledon, coleoptile, mesocotyl, first leaf and apex. The recovery of 14 C-glyphosate was over 86%. For both application treatments, the shoot apex was the major sink of the mobilized glyphosate (47.9 +/- 2.93% for root absorption and 45.8 +/- 2.91% for foliar absorption). Expressed on a tissue fresh weight basis, approximately 0.26 mug a.e. g(-1) of glyphosate in the apex produced a 50% reduction of plant fresh weight (ED50) when the herbicide was applied to the root. However, the ED50 following foliar absorption was only 0.042 mug a.e. g(-1) in the apex, thus maize seedlings were much more sensitive to foliar application of the herbicide.