Factors Affecting Dalapon Absorption and Translocation in Johnsongrass |
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Authors: | C. G. McWHORTER T. N. JORDAN |
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Affiliation: | Southern Weed Science Laboratory, Agricultural Research Service, U.S. Department of Agriculture and Delta Branch of the Mississippi Agricultural and Forestry Experiment Station, Stoneville, MS 38776 |
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Abstract: | The factors affecting the absorption and translocation of 14C-dalapon (2.2-dichloropropionic acid) in johnsongrass were studied. Johnsongrass [Sorghum halepense (L.) Pers.] was first pot-grown in a greenhouse and then treated and placed in controlled-environment chambers. Absorption of 14C-dalapon into johnsongrass leaves and subsequent translocation occurred continuously within the plant during a 48-h period after treatment. Gas chromatographic analysis of johnsongrass extracts showed that the dalapon molecule was translocated intact. Absorption and translocation of 14C-dalapon increased as the droplet volume of the diluent was increased from 0.2 to 5.0 μl per treated spot. At 21 and 32°C, translocation of 14C-dalapon from a 2-cm treated leaf section into the plant was greater at 100% than at 35% relative humidity. At 38°C, translocation was greater at 35% than at 100% relative humidity. The addition of 0.5% surfactant to the dalapon solution increased translocation under all environmental conditions studied. The addition of 0.1 M KH2PO4 to dalapon-surfactant solutions increased 4-dalapon translocation under high temperature (38°C), especially at 35% relative humidity. |
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