Herbicide Retention by Vegetative Buffer Strips from Runoff under Natural Rainfall

Abstract

Effectiveness of vegetative buffer strips for herbicide retention from agricultural runoff was evaluated in a twoyear natural rainfall study. A source area of 0.41 ha (mainly Canisteo silty clay loam soil), having an average slope of 3%, was fall chisel-plowed, spring disked, and planted to corn. Three herbicides (atrazine, metolachlor, and cyanazine) were applied to the source area in each spring. Six vegetative buffer strips, 1.52 m wide ¥ 20.12 m long, were isolated with metal borders downslope of the source area in a well established bromegrass (Bromus inermis) waterway. These strips provided for three replications of two drainage to buffer area ratio treatments of 15:1 and 30:1. Herbicide retention was dependent on the antecedent moisture conditions of the strips. These retentions ranged from 11 to 100% for atrazine, 16 to 100% for metolachlor, and 8 to 100% for cyanazine. Herbicide retention by the buffer strips for the two treatments were not significantly different for the observed storm events. Herbicide concentrations in solution in outflow from the strips were less than the inflow concentrations for all the three herbicides. Infiltration was the key process for herbicide retention by the buffer strips, although there was some adsorption to in-place soil and/or vegetation. Metolachlor concentrations in sediment increased in outflow for the two treatments; however, the opposite was true for atrazine and cyanazine. Herbicide retention by sediment deposition in the strip represented about 5% of the total herbicide retention by the buffer strips. The buffer strips were found to have high percent sediment retention, ranging from 40 to 100%; thus, the strips would be more effective for retaining strongly adsorbed herbicides.

Role of the GLUT 2 Glucose Transporter in the Response of the L-type Pyruvate Kinase Gene to Glucose in Liver-derived Cells

“…5A also shows that mhAT3F cells expressed the GLUT 1 and HK 1 genes regardless of the presence of glucose in the medium and with a low sensitivity to translation inhibitors. In contrast, these cells, like all the lines used in this study or reported in the literature (2,8,9), were devoid of glucokinase gene expression (not shown).…”

“…In the hepatoma cell lines de- scribed to date, neither GLUT 2 nor glucokinase were ever reported to be significantly expressed, being replaced by GLUT 1 and insulin-independent hexokinase isoforms, mainly HK 1 (8,16). We have previously established and characterized various new hepatoma cell lines, some of which express GLUT 2 but not glucokinase and yet are responsive to glucose (2,19,20).…”

“…Glucose phosphorylation to glucose 6-phosphate, required for glucose action on the transcriptional machinery (2)(3)(4)(5)(6), is mainly mediated by hexokinase (HK) 1 II in adipocytes and by hexokinase IV (or glucokinase) in the liver and ␤ cells; expression of the glucokinase gene is constitutive in the pancreas and insulin-dependent in the liver due to the existence of two different tissue-specific alternative promoters (7). However, glucokinase is replaced by other insulin-independent hexokinase isoforms (mainly HK I) in cultured hepatoma cell lines (2,8,9). Tissues whose function is regulated by glucose also possess particular glucose transporters, GLUT 4 in adipocytes and GLUT 2 in tissues secreting glucose into the blood (liver, small intestine, and proximal tubular cells of the kidney) as well as GLUT 2 in the ␤ cells of the islets of Langerhans (10,11).…”

“…In fact, expression of glucose-responsive genes is generally constitutive in these cells in which glucokinase is replaced by HK I and GLUT 2 is replaced by GLUT 1, another glucose transporter isoform expressed in most cells not specialized in metabolism regulation, e.g. in cancerous cells (8,16).…”

Effect of Extracellular AMP on Cell Proliferation and Metabolism of Breast Cancer Cell Lines with High and Low Glycolytic Rates

“…Data from former reports suggest that there are many factors contributing to the origin of aerobic glycolysis (2). The altered control of glycolysis by expression of certain isoenzymes is one important factor (2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12). Furthermore, the glycerol 3-phosphate shuttle and the malate-aspartate shuttle are altered in such a way that transport of cytosolic hydrogen into the mitochondria is reduced, requiring tumor cells to reoxidize NADH cytosolically by lactate dehydrogenase (13)(14)(15).…”