TY - JOUR TI - Effects of pH and organic acids on orthophosphate solubility in an acidic, montmorillonitic soil. AU - Traina, S.J. AU - Sposito, G. AU - Hesterberg, D. AU - Kafkafi, U. T2 - Soil Science Society of America Journal AB - Abstract The effects of pH and organic acid addition on residual orthophosphate ( o ‐phosphate) solubility in an acidic, montmorillonitic soil separate suspended in 20 mol NaCl m −3 were investigated. In the absence of added organic acid, the solubility of residual o ‐phosphate in the soil decreased as the pH value was increased from 4 to 7. With o ‐phosphate additions that resulted in low aqueous‐solution o ‐phosphate concentrations, the soil sorbed more o ‐phosphate at pH 7 than at 5.5. The solubility data appeared consistent with the presence of an Al‐phosphate solid whose formation was initiated through the hydrolysis of exchangeable Al 3+ and subsequent reaction of the hydrolytic product with o ‐phosphate in aqueous solution. Additions of citric, tartaric, or formic acid at low concentrations (<0.1 mol m −3 ) produced a drop in residual o ‐phosphate solubility at pH 5.5 and 7.0. In the case of citric acid, o ‐phosphate solubility gradually returned to its value in the absence of organic ligand as the ligand concentration was increased to 0.6 mol m −3 , whereas no such increase occurred in the case of tartaric or formic acid. This behavior was rationalized as the outcome principally of two competing reactions: (i) the reaction of adsorbed, polymeric hydroxy‐Al with organic ligand to form an exchangeable Al species that combined with o ‐phosphate to reduce its solubility, and (ii) the complexation of adsorbed Al to form a soluble Al‐organic complex that did not subsequently combine with o ‐phosphate. The latter reaction was important only for citric acid. The former reaction, favored by a large stability constant for Al‐organic acid adducts, produced o ‐phosphate solubility decreases in the order citrate > tartrate > formate. DA - 1986/// PY - 1986/// DO - 10.2136/sssaj1986.03615995005000010009x VL - 50 IS - 1 SP - 45-52 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-0022927967&partnerID=MN8TOARS ER - TY - JOUR TI - Calcium-magnesium exchange on illite in the presence of adsorbed sodium. AU - Sposito, G. AU - Levesque, C.S. AU - Hesterberg, D. T2 - Soil Science Society of America Journal AB - Abstract Binary and ternary cation exchange experiments were performed with Na + , Ca 2+ , and Mg 2+ on Silver Hill illite and on a soil illite suspended in 50 mol m −3 perchlorate at pH 7. The binary experiments indicated no preference for Ca over Mg on the specimen illite, but selectivity for bivalent cations over Na + and for Ca 2+ over Mg 2+ on the soil illite. The ternary exchange data showed that, for both illites, there was no effect of adsorbed Na on the Ca‐Mg exchange isotherm at exchangeable sodium percentages from 0 to 30%, either for freshly‐prepared clay suspensions or for those aged up to 270 d in NaClO 4 . No significant differences in the total adsorbed metal charge ( Q o ) were observed among the binary and ternary exchange experiments, and Q o was independent of the degree of bivalent cation saturation ( E Ca or E Mg ) in the Na → Ca and Na → Mg exchange experiments on the soil illite. The Vanselow selectivity coefficient for Mg → Ca exchange on the soil illite decreased as E Ca increased, showing a plateau near E Ca ≈ 0.6 and dropping to 1.0 as E Ca became equal to 1.0. This behavior was interpreted as evidence for at least two classes of surface complex involving Ca and Mg. DA - 1986/// PY - 1986/// DO - 10.2136/sssaj1986.03615995005000040015x VL - 50 IS - 4 SP - 905-909 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-0022928345&partnerID=MN8TOARS ER - TY - JOUR TI - Effects of ionic strength, calcium, and citrate on orthophosphate solubility in an acidic, montmorillonitic soil. AU - Traina, S.J. AU - Sposito, G. AU - Hesterberg, D. AU - Kafkafi, U. T2 - Soil Science Society of America Journal AB - Abstract A recent study by the authors of the effects of pH and organic acids on residual orthophosphate solubility in an acidic, montmorillonitic soil (Typic Chromoxererts) was extended to include variations of ionic strength (NaCl background) and Ca 2+ concentration at fixed ionic strength. The objective of the experiments was to elucidate further the mechanism of orthophosphate solubility in a montmorillonitic soil containing exchangeable Al(III) and added citric acid. At ionic strengths between 20 and 100 mol m −3 (NaCl) and Ca 2+ concentrations between 1 and 5 mol m −3 at 20 mol m −3 ionic strength (NaCl background), additions of citric acid at low concentrations (<0.1 mol m −3 ) reduced orthophosphate solubility. The solubility then gradually returned to its value in the absence of added organic acid as the citric acid concentration was increased to 0.6 mol m −3 . The only significant effect of increasing the ionic strength or the Ca 2+ concentration was to decrease orthophosphate solubility at any level of citric acid addition. Orthophosphate‐citric acid interactions in the soil were influenced only quantitatively, probably through the displacement of exchangeable Al(III) by Na + and/or Ca 2+ , by increasing the concentration of these two metal cations in the soil solution. DA - 1986/// PY - 1986/// DO - 10.2136/sssaj1986.03615995005000030016x VL - 50 IS - 3 SP - 623-627 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-0022927570&partnerID=MN8TOARS ER - TY - BOOK TI - Multiproduct yield tables for single-thinned loblolly pine [Pinus taeda] plantations AU - Smith, W. D. AU - Hafley, W. L. DA - 1986/// PY - 1986/// PB - Raleigh, N.C.: NCSU School of Forest Resources SE - 77 ER - TY - JOUR TI - TRANSPORT OF ROSETTES FROM THE GOLGI-APPARATUS TO THE PLASMA-MEMBRANE IN ISOLATED MESOPHYLL-CELLS OF ZINNIA-ELEGANS DURING DIFFERENTIATION TO TRACHEARY ELEMENTS IN SUSPENSION-CULTURE AU - HAIGLER, CH AU - BROWN, RM T2 - PROTOPLASMA DA - 1986/// PY - 1986/// DO - 10.1007/BF01275709 VL - 134 IS - 2-3 SP - 111-120 SN - 1615-6102 ER - TY - JOUR TI - ABSCISIC-ACID CONTROL OF LECTIN ACCUMULATION IN WHEAT SEEDLINGS AND CALLUS-CULTURES - EFFECTS OF EXOGENOUS ABA AND FLURIDONE AU - RAIKHEL, NV AU - PALEVITZ, BA AU - HAIGLER, CH T2 - PLANT PHYSIOLOGY AB - Wheat germ agglutinin is found in wheat embryos and a similar lectin is present in the roots of older plants. We report here that 10 micromolar abscisic acid (ABA) produces an average two to three-fold enhancement in the amount of lectin in the shoot base and the terminal portion of the root system of hydroponically grown wheat seedlings. Although ABA stunts seedling growth, a similar growth inhibition produced by ancymidol is not accompanied by elevated lectin levels. To further clarify the role of ABA, wheat callus cultures were employed. Callus derived from immature embryos was grown on growth medium containing various combinations of ABA and 2,4-dichlorophenoxyacetic acid. Those grown in the presence of 10 micromolar ABA exhibit the largest increases in lectin compared to material grown on other regimes. The involvement of ABA in lectin accumulation was further probed with fluridone, an inhibitor of carotenoid synthesis which has also been linked to depressed levels of endogenous ABA. Wheat seedlings grown in the presence of 1 or 10 milligrams per liter fluridone have few or no carotenoids, and wheat germ agglutinin levels in the shoot base and roots are lower compared to controls. The greatest effect (a 39% reduction in the shoot base) is produced at an herbicide concentration of 10 milligrams per liter. Exogenous 10 micromolar ABA greatly stimulates lectin accumulation in the presence of fluridone, but the levels are not as high as those produced by ABA alone. These results indicate that lectin synthesis is under ABA control in both wheat embryos and adult plants. DA - 1986/1// PY - 1986/1// DO - 10.1104/pp.80.1.167 VL - 80 IS - 1 SP - 167-171 SN - 1532-2548 ER - TY - JOUR TI - Novel recombinations in the maize mitochondrial genome produce a unique transcriptional unit in the texas male-sterile cytoplasm AU - Dewey, R. E. AU - Levings, C. S. AU - Timothy, D. H. T2 - Cell AB - We have characterized a 3547 bp DNA fragment from male-sterile (cms-T) maize mitochondria, designated TURF 2H3, selected because of its unique and abundant transcripts. Sequence analysis indicated that TURF 2H3 originated by recombinations among portions of the flanking and/or coding regions of the maize mitochondrial 26S ribosomal gene, the ATPase subunit 6 gene, and the chloroplast tRNA-Arg gene. TURF 2H3 contains two long open reading frames that could encode polypeptides of 12,961 Mr and 24,675 Mr. The larger open reading frame hybridizes to transcripts in all maize cytoplasms, the smaller to transcripts only in T cytoplasm. TURF 2H3 transcripts appear to be uniquely altered in cms-T plants restored to fertility by the nuclear restorer genes Rf1 and Rf2. A possible relationship between TURF 2H3, nuclear restorer genes, and the male sterility trait in T cytoplasm is suggested. DA - 1986/// PY - 1986/// DO - 10.1016/0092-8674(86)90465-4 VL - 44 IS - 3 SP - 439-449 ER -