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Selected Works

1997

Articles 1 - 8 of 8

Full-Text Articles in Plant Sciences

Wounding-Induced Cell Wall Ph Shifts In Coleoptile Segments Of Various Poaceae, Winfried Peters Jul 1997

Wounding-Induced Cell Wall Ph Shifts In Coleoptile Segments Of Various Poaceae, Winfried Peters

Winfried S. Peters

Wounding-induced extracellular pH shifts were characterized previously in excised segments of maize (Zea mays L.) coleoptiles. In the present study it is demonstrated that similar pH shifts also occur in Triticum aestivum L., Secale cereale L., Hordeum vulgare L., Avena sativa L., Sorghum durra (Forsk.) Stapf, and Setaria italica (L.) Beauv., with characteristic quantitative differences between the species. Indole-acetic acid induces pronounced drops of the medium pH in all species except Setaria italica.

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Iaa Breakdown And Its Effect On Auxin-Induced Cell Wall Acidification In Maize Coleoptile Segments, Winfried Peters, Christa Lommel, Hubert Felle Jun 1997

Iaa Breakdown And Its Effect On Auxin-Induced Cell Wall Acidification In Maize Coleoptile Segments, Winfried Peters, Christa Lommel, Hubert Felle

Winfried S. Peters

In excised Zea mays L. coleoptiles incubated in aerated media at high fresh weight per volume ratios, indole-3-acetic acid induces transient drops of extracellular pH. Based on the quantitative dependency of the response on the initial auxin concentration we developed a novel auxin bioassay, which allows reliable estimation of IAA concentrations between 10−8.5 and 10−5 M. Using the bioassay and complementary concentration measurements by IAA fluorescence we found the transient IAA-induced pH response paralleled by a decrease of auxin activity and concentration in the medium. This decline is rapid and starts immediately upon auxin addition, and insofar differs from the …

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Spiroplasma Chrysopicola Sp. Nov., Spiroplasma Gladiatoris Sp. Nov., Spiroplasma Helicoides Sp. Nov., And Spiroplasma Tabanidicola Sp. Nov., From Tabanid (Diptera: Tabanidae) Flies, Robert F. Whitcomb, Frank E. French, Joseph G. Tully, Gail E. Gasparich, David L. Rose, Patricia Carle, Joseph M. Bove, Roberta B. Henegar, Meghnad Konai, Kevin J. Hackett, Jean R. Adams, Truman B. Clark, David L. Williamson Jun 1997

Spiroplasma Chrysopicola Sp. Nov., Spiroplasma Gladiatoris Sp. Nov., Spiroplasma Helicoides Sp. Nov., And Spiroplasma Tabanidicola Sp. Nov., From Tabanid (Diptera: Tabanidae) Flies, Robert F. Whitcomb, Frank E. French, Joseph G. Tully, Gail E. Gasparich, David L. Rose, Patricia Carle, Joseph M. Bove, Roberta B. Henegar, Meghnad Konai, Kevin J. Hackett, Jean R. Adams, Truman B. Clark, David L. Williamson

Gail Gasparich

Four spiroplasma strains, DF-1T, TG-1T, TABS-2T, and TAUS-1T, all of which were isolated from deerflies or horseflies (Diptera: Tabanidae), were serologically distinct from previously described spiroplasma species, groups, and subgroups. Strain DF-1Toriginated from a Maryland deerfly (Chrysops sp.); strain TG-1Twas isolated from a Maryland horsefly (Tabanus gladiator); strain TAUS-1Toriginated from a member of the Tabanus abdominalis-limbatinevris complex of horseflies collected in Maryland; and strain TABS-2Twas isolated from a horsefly (Tabanus abactor) collected in Oklahoma. Cells of all of the strains appeared to be helical and motile when they were examined by dark-field microscopy. Cells of strain DF-1Tgrowing in M1D medium …

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The Determination Of Relative Elemental Growth Rate Profiles From Segmental Growth Rates (A Methodological Evaluation), Winfried Peters, Nirit Bernstein Mar 1997

The Determination Of Relative Elemental Growth Rate Profiles From Segmental Growth Rates (A Methodological Evaluation), Winfried Peters, Nirit Bernstein

Winfried S. Peters

Relative elemental growth rate (REGR) profiles describe spatial patterns of growth intensity; they are indispensable for causal growth analyses. Published methods of REGR profile determination from marking experiments fall in two classes: the profile is either described by a series of segmental growth rates, or calculated as the slope of a function describing the displacement velocities of points along the organ. The latter technique is usually considered superior for theoretical reasons, but to our knowledge, no comparative methodological study of the two approaches is currently available. We formulated a model REGR profile that resembles those reported from primary roots. We …

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Selective Predation On The Seeds Of Woody Plants, Scott J. Meiners, Edmund W. Stiles Jan 1997

Selective Predation On The Seeds Of Woody Plants, Scott J. Meiners, Edmund W. Stiles

Scott J. Meiners

Selective predation on the seeds of woody plants. J. Torrey Bot. Soc. 124: 67-70). 1997.-Seed predation may be an important factor influencing the structure of successional plant communities. We used a cafeteria-style experiment, placed in an old field and an early successional forest, to determine predator preferences for seeds of nine species of woody plants. Intensity of seed predation was equivalent in both sites. Seed predators preferred Acer saccharum, flex vertic illata, and Viburnum dentatum, but this was not related to seed mass. Predation intensity was more variable in the old field than in the forest, possibly related to the …

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Isolation Of A Mannose-Binding And Ige- And Igm-Reactive Lectin From The Seeds Of Artocarpus Integer, Onn Haji Hashim Jan 1997

Isolation Of A Mannose-Binding And Ige- And Igm-Reactive Lectin From The Seeds Of Artocarpus Integer, Onn Haji Hashim

Onn Haji Hashim

A mannose-binding lectin, termed champedak lectin-M, was isolated from an extract of the crude seeds of champedak (Artocarpus integer). On gel filtration chromatography, the lectin eluted in a single peak at elution volumes corresponding to 64 kDa, SDS-PAGE showed the mannose-binding lectin to be composed of 16.8 kDa polypeptides with some of the polypeptides being disulphide-linked to give dimers. When tested with all isotypes of immunoglobulins, champedak lectin-M demonstrated a selective strong interaction with human IgE and IgM, and a weak interaction with IgA2, The binding interactions of lectin-M were metal ion independent. The lectin was also shown to interact …

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Effects Of Elevated Co2 And Defoliation On Grasses: A Comparative Ecosystem Approach, Brian J. Wilsey, James S. Coleman, Samuel J. Mcnaughton Jan 1997

Effects Of Elevated Co2 And Defoliation On Grasses: A Comparative Ecosystem Approach, Brian J. Wilsey, James S. Coleman, Samuel J. Mcnaughton

Brian J. Wilsey

Three plant species from each of three grassland ecosystems were grown under elevated (700 mL/m3) and ambient (350 mL/m3) CO2 and were defoliated or left undefoliated to test whether species response to elevated CO2 and grazing is related to evolutionary grazing history or to mode of photosynthesis. The three ecosystems represented a tropical grassland dominated by C4 species (the Serengeti of Africa), a temperate grassland dominated by a mixture of C3 and C4 species (Flooding Pampa of South America), and a northern temperate grassland dominated by C3 species (Yellowstone National Park of North America). Plants were grown in growth chambers …

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The Spiroplasma Motility Inhibition Test, A New Method For Determining Intraspecific Variation Among Colorado Potato Beetle Spiroplasmas, Kevin J. Hackett, J. J. Lipa, G. E. Gasparich, D. E. Lynn, M. Konai, M. Camp, R. F. Whitcomb Dec 1996

The Spiroplasma Motility Inhibition Test, A New Method For Determining Intraspecific Variation Among Colorado Potato Beetle Spiroplasmas, Kevin J. Hackett, J. J. Lipa, G. E. Gasparich, D. E. Lynn, M. Konai, M. Camp, R. F. Whitcomb

Gail Gasparich

The Colorado potato beetle, Leptinotarsa decemlineata, is a major holarctic pest of solanaceous crops. Presumably, this insect spread from Solanum species in central America to the Mexican plateau, and this was followed by multiple invasions of North America and Europe. Attempts are being made to control this beetle by using a genetically modified spiroplasma that occurs naturally in its gut. In the current study, spiroplasmas isolated from beetles collected in North America and Poland exhibited serologic (spiroplasma motility inhibition test) and genomic (restriction fragment length polymorphism) profiles that suggest that there were multiple spiroplasma introductions. Two serovars were identified; one …

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