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Öğe Herbicide Penetration Through Isolated Periderm and Cuticular Membranes(TAYLOR & FRANCIS LTD, 1996) Ersöz, Mustafa; Duncan, Harry J.; Lale, Mustafa; Uçan, Halil I.The penetration of three herbicides through isolated potato periderm (PM) and pear fruit cuticular membranes (PFCM) as their commercial formulations was examined in two separate experimental methods involving infinite and finite dose systems. The permeability of the three herbicides was found to follow the order of their water solubility re. amitrole> glyphosate> asulam. The results obtained using the infinite and finite dose systems are in general agreement. All three herbicides penetrated rapidly through the PM and PFCM during the initial 1 h treatment period then decreased. The results showed that the penetration for three herbicides under examination depends on water solubility, and also is significantly affected by pH.Öğe Ion-Exchange Selectivities of Periderm and Cuticular Membranes Toward Alkali Cations(TAYLOR & FRANCIS INC, 1994) Ersöz, Mustafa; Duncan, Harry J.The ion-exchange selectivities of lithium, sodium, potassium, and cesium on isolated potato periderm (Solanum tuberosum) and pear fruit cuticular membranes were investigated; the general order of preference both for cation selectivities and ion-exchange capacities was lithium > sodium > potassium > cesium. The potato periderm and pear fruit cuticular membranes exhibited a behavior typical of ion-exchange resins of the weak acid type. At constant pH 7, the ion-exchange capacities of periderm and cuticular membranes increased with hydrated ionic radius, and also with increasing pH and neutral salt concentration, and decreased with crystal ionic radius. Counterion selectivities also exhibited the same behavior. The ion-exchange properties are discussed in terms of the structure and function of potato periderm and pear fruit cuticular membranes.Öğe Sorption of Heavy-Metal Ions on New Metal-Ligand Complexes Chemically Derived From Lycopodium-Clavatum(MARCEL DEKKER INC, 1994) Pehlivan, Erol; Ersöz, Mustafa; Yıldız, Salih; Duncan, Harry J.Sorption of heavy metal ions from aqueous solution has been investigated as a function of pH using a novel exchanger system whereby Lycopodium clavatum is functionalized with carboxylate and glyoxime metal-ligand complexes. The new ligand exchangers were prepared using a reaction of diaminosporopollenin with various metal-ligand complexes of glyoxime and monocarboxylic acid. The sorptive behavior of these metal-ligand exchangers and the possibilities to remove and to recover selectively heavy metal cations using these systems are discussed on the basis of their chemical natures and their complexing properties.Öğe Transport and Selectivities of Amino-Acids on Periderm and Cuticular Membranes(TAYLOR & FRANCIS INC, 1995) Ersöz, Mustafa; Vural, Ufuk S.; Duncan, Harry J.The transport of amino acids through isolated potato periderm and pear fruit cuticular membranes were investigated. The transport rate depended on the molecular size of amino acids and decreased with an increase in molecular size through extension of the hydrophobic -CH2- group. The selectivity coefficients of amino acids for the ammonium ion form of periderm and cuticular membranes were also determined, using the mass action law. They were found to be correlated with various physicochemical parameters such as the partial molar volume and the molecular weight.Öğe Transport of K+ Ion and Selective Transport of Alkali Cations Through Periderm and Cuticular Membranes(ELSEVIER SCIENCE BV, 1996) Ersöz, Mustafa; Duncan, Harry J.The transport of K+ ion against its concentration gradient through isolated periderm (PM) and cuticular (PFCM) membranes at different pH and salt concentrations was investigated. The mean transport rate and transport fraction were calculated, and a tentative transport mechanism due to fixed charges was proposed. The transport system depends on the concentration gradient of K+ ions and H+ ions and the pH gradient was the main driving force. This system is characterised by asymmetry of binding on both compartments of the membrane for the formation and dissociation of carrier carboxyl groups in the membrane matrix. These carrier groups are dissociated at high pH ranges. The studies were then extended to examine the selective transport of alkali cations by using K-Na and K-Li binary systems with various pH gradients. In the transport of metal ions, the selectivity depends on both the hydrated ionic size and the interaction between the carboxyl groups in the membrane and the metal ions.
