Factors Affecting Dalapon Absorption and Translocation in Johnsongrass

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.

Effect of Temperature and Relative Humidity on Translocation of14C-Metriflufen in Johnsongrass (Sorghum halepense) and Soybean (Glycine max)

“…location at 40% vs. 100% RH. This comparative lack of effect of RH on metriflufen translocation is in contrast to results obtained in studies with mefluidide, dalapon, bentazon, and glyphosate (3,8,9,10,14).…”

“…Translocation of 14 C was greater with 100% RH than with 40% RH at 18 and 27 C, but not at 35 C (Table 1). Similar results have been reported for the translocation of dalapon (8). Perhaps the effects of RH on the transpiration rate of johnsongrass may have reduced the metriflufen movement.…”

“…The amount of 14 C-activity remaInIng on the surface of the treated leaf after 48 h varied from 1.6 to 27.1 % of the total applied. The amounts remaining on the surface of the treated leaf were generally much smaller than values reported for mefluidide, glyphosate, or dalapon in johnsongrass (8,9,10).…”

Survey of Winter Wheat (Triticum aestivum) Stubble Fields Sprayed with Herbicides After Harvest in 1986

“…Weed species probably react differently with temperature, soil moisture, and rela tive humidity variations. High air temperatures have lowered efficacy with other herbicides (7,13). When the temperatures were near 38 C or above, glyphosate movement into the plant possibly was reduced.…”

Control of Three Weed Species in Sugarbeets (Beta vulgaris) with an Electrical Discharge System

“…The chemical dl-strigol (ST) was first synthesized in 1974 (14). Other growth regulators that stimulate witch weed seed germination include kinetin (22, 23), scopoletin (21), and ethylene (7,8,10). Egley (7) reported that gibberellic acid had no apparent effect on non -scarified seeds, but promoted germination of scarified seeds.…”