Plant Physiology

Knox, J. Paul; Beale, Michael H.; Butcher, Geoffrey W.; MacMillan, Jake

doi: 10.1104/pp.88.4.959pmid: 16666484

Abstract The production and characterization of two high affinity rat monoclonal antibodies to 13-deoxy-gibberellins is described. Hybrid myelomas were derived from rats immunized with an immunogenic keyhole limpet hemocyanin-gibberellin conjugate, linked at carbon-3 to gibberellin A4 via a hemisuccinate bridge. The selected monoclonal antibodies were characterized by a competitive radioimmunoassay. 1 Present address: John Innes Institute, Colney Lane, Norwich NR4 7UH, U.K. This content is only available as a PDF. © 1988 American Society of Plant Biologists This article is published and distributed under the terms of the Oxford University Press, Standard Journals Publication Model (https://academic.oup.com/journals/pages/open_access/funder_policies/chorus/standard_publication_model)

Joyard, Jacques; Forest, Eric; Blée, Elizabeth; Douce, Roland

doi: 10.1104/pp.88.4.961pmid: 16666485

Abstract Incubation of intact spinach (Spinacia oleracea L.) chloroplasts in the presence of 35SO42− resulted in the light-dependent formation of a chloroform-soluble sulfur-containing compound distinct from sulfolipid. We have identified this compound as the most stable form (S8) of elemental sulfur (S0, valence state for S = O) by mass spectrometry. It is possible that elemental sulfur (S0) was formed by oxidation of bound sulfide, i.e. after the photoreduction of sulfate to sulfide by intact chloroplasts, and released as S8 under the experimental conditions used for analysis. This content is only available as a PDF. © 1988 American Society of Plant Biologists This article is published and distributed under the terms of the Oxford University Press, Standard Journals Publication Model (https://academic.oup.com/journals/pages/open_access/funder_policies/chorus/standard_publication_model)

Callis, Judy; Fromm, Michael; Walbot, Virginia

doi: 10.1104/pp.88.4.965pmid: 16666486

Abstract The response of maize (Zea mays L.) protoplasts to high temperature stress was investigated. After isolation and electroporation, protoplasts were preincubated for 12 hours at 26°C then incubated for 6 hours at elevated temperatures. The pattern of polypeptides synthesized by these protoplasts during the last hour was monitored by in vivo labeling with 35S-methionine. Incubation at 40° and 42°C resulted in the synthesis of polypeptides not detectable at 26°C. Introduction of a chimeric maize heat shock protein 70 promoter-chloramphenicol acetyltransferase coding region gene into protoplasts via electroporation resulted in the temperature-dependent induction of chloramphenicol acetyltransferase activity with maximal activity at 40°C. In the same protoplasts, a second chimeric gene, in which the firefly luciferase coding region was under the control of the 35S promoter from cauliflower mosaic virus, did not show an increase in expression after incubation at higher temperatures. Maize protoplasts provide a system to study molecular responses to high temperature stress. 2 Present address: Horticulture Department, University of Wisconsin, Madison, WI 53706. 3 Present address: USDA-PGEC, 800 Buchanan St., Albany, CA 94710. 1 Supported by National Institutes of Health grant GM32422 to V. W. and by a gift from Pioneer Hi-Bred International. This content is only available as a PDF. © 1988 American Society of Plant Biologists This article is published and distributed under the terms of the Oxford University Press, Standard Journals Publication Model (https://academic.oup.com/journals/pages/open_access/funder_policies/chorus/standard_publication_model)

Vergne, Philippe; Dumas, Christian

doi: 10.1104/pp.88.4.969pmid: 16666487

Abstract Procedures have been designed to isolate viable immature male gametophytes from wheat (Triticum aestivum L.) anthers of different stages of development. Maceration of anthers by a micro-blender allowed for the release of numerous intact vacuolate microspores. Tris-buffered media prevented tricellular pollen grains from bursting during the isolation procedure. Proteins from the undamaged male gametophytes have been analyzed by isoelectric focusing and sodium dodecyl sulfate-polyacryl-amide gel electrophoresis. A set of new proteins was detected at the onset of the second pollen grain mitosis. The results demonstrate the opportunity for studies on haploid gene expression at the translational level. 1 Supported in part by a Rhône-Poulenc Agrochimie doctoral fellowship awarded to P.V. This content is only available as a PDF. © 1988 American Society of Plant Biologists This article is published and distributed under the terms of the Oxford University Press, Standard Journals Publication Model (https://academic.oup.com/journals/pages/open_access/funder_policies/chorus/standard_publication_model)

Rebeille, Fabrice; Gans, Pierre

doi: 10.1104/pp.88.4.973pmid: 16666488

Abstract In a mutant strain of Chlamydomonas reinhardtii devoid of active ribulose 1,5-bisphosphate carboxylase oxygenase, the addition of mitochondrial inhibitors in the dark resulted in a pronounced decrease in cellular ATP, a fall of the glucose 6-phosphate content, and a rise of the NADPH concentration. These biochemical changes were accompanied by an increase of the fluorescence level, showing changes in the redox state of the chloroplastic electron transport chain. Similar results were obtained in presence of an uncoupler. These data indicated that alterations in the mitochondrial electron transport chain in dark could affect the chloroplastic chain, probably through variations of the glycolysis activity. When mitochondrial oxidases were blocked, illumination of the algae reversed the effect of the inhibitors on the ATP and glucose 6-phosphate concentrations. This last result suggested that the chloroplastic photophosphorylations in these algae played a major role in the control of the glycolytic flux. This content is only available as a PDF. © 1988 American Society of Plant Biologists This article is published and distributed under the terms of the Oxford University Press, Standard Journals Publication Model (https://academic.oup.com/journals/pages/open_access/funder_policies/chorus/standard_publication_model)

Wedding, Randolph T.; Rustin, Pierre; Meyer, Christopher R.; Black, M. Kay

doi: 10.1104/pp.88.4.976pmid: 16666489

Abstract Phosphoenolpyruvate carboxylase isolated from maize (Zea mays L.) leaves was assayed with varying concentrations of free phosphoenolpyruvate at several fixed-varying concentrations of free magnesium higher than required to saturate the enzyme reaction. These assays produced velocity data which were found to form a family of individual lines when plotted against free phosphoenolpyruvate or against total phosphoenolpyruvate, but not when plotted against the concentration of the complex of phosphoenolpyruvate with magnesium. In this latter case, the points from all the fixed-varying concentrations fell on the same line, which can be fitted to a modified Michaelis-Menten equation with a multiple correlation coefficient R2 = 0.995. Similar results were obtained when the enzyme from the C4 plant maize was assayed with manganese rather than magnesium and when phosphoenolpyruvate carboxylase from leaves of the C3 plant wheat (Triticum vulgare Vill.) was assayed with magnesium. However, at pH 7.0 the enzyme from the Crassulacean acid metabolism plant Crassula argentea did not produce a satisfactory single line when plotted against the complex of metal ion and substrate, but did so when the assay pH was raised to 8.0. It is concluded that in general the preferred form of substrate for phosphoenolpyruvate carboxylase is the complex of phosphoenolpyruvate with the metal ion. 2 Permanent address: Laboratoire de Biologie Vegetale IV (CNRS, UA 1180) Universite Pierre et Marie Curie, Paris 75005, France. Recipient of a CNAM/CAB/NATO grant. 1 Supported in part by National Science Foundation grant PCMB 85-15181. This content is only available as a PDF. © 1988 American Society of Plant Biologists This article is published and distributed under the terms of the Oxford University Press, Standard Journals Publication Model (https://academic.oup.com/journals/pages/open_access/funder_policies/chorus/standard_publication_model)

Galloway, Cynthia M.; Dugger, W. M.; Black, C. C.

doi: 10.1104/pp.88.4.980pmid: 16666490

Abstract Fructose 2,6-bisphosphate inhibits phosphoglucomutase noncompetitively with respect to the cofactor glucose 1,6-bisphosphate. Previous studies from our laboratory had shown that phosphoglucomutase was activated by fructose 2,6-bisphosphate in the absence of added glucose 1,6-bisphosphate. The fructose 2,6-bisphosphate activation previously reported was due to the presence of glucose 1,6-bisphosphate in the commercial preparation of fructose 2,6-bisphosphate. 2 Present address: Department of Biochemistry, University of Georgia, Athens, GA 30602. 1 This research was supported in part by a Chancellor's Patent Fund Award to C. M. G. and by the California Agricultural Experiment Station. This content is only available as a PDF. © 1988 American Society of Plant Biologists This article is published and distributed under the terms of the Oxford University Press, Standard Journals Publication Model (https://academic.oup.com/journals/pages/open_access/funder_policies/chorus/standard_publication_model)

Das, Gitali; Sen-Mandi, Swati

doi: 10.1104/pp.88.4.983pmid: 16666491

Abstract Inability of aged seeds to grow into successful plants in the field is primarily due to their age-associated loss of rooting ability. The present work describes an attempt to initiate roots in nonrooting aged embryos of wheat (Triticum aestivum L.). Data presented give a comparative study of root formation and seedling growth on different culture media. Such studies indicate that sucrose alone is enough to bring about root development in nonrooting aged embryos. This content is only available as a PDF. © 1988 American Society of Plant Biologists This article is published and distributed under the terms of the Oxford University Press, Standard Journals Publication Model (https://academic.oup.com/journals/pages/open_access/funder_policies/chorus/standard_publication_model)

Ishida, Betty K.; Palmer, John M.

doi: 10.1104/pp.88.4.987pmid: 16666492

Abstract Direct evidence is presented for the lack of a pH change in the medium associated with electron flow along the alternative, cyanide-resistant pathway in Arum maculatum mitochondria. When these mitochondria oxidize succinate via the cytochrome chain, the medium becomes acidified. However, when the main respiratory chain is blocked by cyanide or antimycin A, oxygen consumption continues, but no pH change occurs. This confirms the lack of a charge separation across the membrane, so that phosphorylation cannot be supported during operation of the alternative oxidase. This content is only available as a PDF. © 1988 American Society of Plant Biologists This article is published and distributed under the terms of the Oxford University Press, Standard Journals Publication Model (https://academic.oup.com/journals/pages/open_access/funder_policies/chorus/standard_publication_model)

Wenck, Allan R.; Conger, Bob V.; Trigiano, Robert N.; Sams, Carl E.

doi: 10.1104/pp.88.4.990pmid: 16666493

Abstract Endogenous indoleacetic acid (IAA) and cytokinin concentrations were measured by high performance liquid chromatography in leaf sections of an orchardgrass (Dactylis glomerata L.) genotype which exhibited a high capacity for somatic embryogenesis in vitro and in two genotypes that did not exhibit this capacity. The nonembryogenic genotypes contained 3- to 4-fold higher concentrations of zeatin, zeatin riboside, dihydrozeatin, dihydrozeatin riboside, and total cytokinins than the embryogenic genotype. There were no significant differences in IAA concentrations between genotypes. Cytokinin concentrations between basal and distal sections of embryogenic genotype were not different, but the IAA concentration was significantly greater in basal sections. Somatic embryogenesis was inhibited in the embryogenic genotype by 0.001 micromolar exogenously added zeatin. 1 Supported in part by U.S. Department of Agriculture-Competitive Research Grants Office grant 86-CRCR-1-2215. This content is only available as a PDF. © 1988 American Society of Plant Biologists This article is published and distributed under the terms of the Oxford University Press, Standard Journals Publication Model (https://academic.oup.com/journals/pages/open_access/funder_policies/chorus/standard_publication_model)