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Water-Deficit Stress Tolerance Differs between Two Locoweed Genera (Astragalus and Oxytropis) with Fungal Endophytes
- Nina Klypina, Matthew Pinch, Brian J. Schutte, Janakiraman Maruthavanan, Tracy M. Sterling
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- Journal:
- Weed Science / Volume 65 / Issue 5 / September 2017
- Published online by Cambridge University Press:
- 30 June 2017, pp. 626-638
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Locoweeds are plants of the genera Astragalus and Oxytropis (Fabaceae family) and are toxic to cattle, sheep, and horses. The toxic property of locoweeds is due to the alkaloid swainsonine (SWA), which is synthesized by an endophytic fungus Alternaria spp. section Undifilum. Although the endophyte–locoweed complex is often considered mutualistic, empirical evidence for benefits to host plants is lacking. This study: 1) compared the growth, photosynthesis, and leaf pigment and antioxidant concentrations between endophyte-infected and endophyte-free plants under well-watered and water-deficit conditions; and 2) measured SWA to determine whether SWA concentrations are attenuated by water deficit and leaf age. Locoweed species in this study were woolly loco and silky crazyweed. Endophyte-infected and endophyte-free (by removal of seed coat) seedlings, as confirmed by DNA analyses, were grown under greenhouse conditions for 6 mo, after which plants were subjected to three 12- to 15-d water-deficit periods that created sublethal drought conditions. Results suggest that the endophyte did not influence photosynthetic gas exchange and leaf pigment concentrations. Under well-watered conditions only, endophyte-infected woolly loco plants had lower shoot and root biomass and higher concentrations of α-tocopherol than endophyte-free plants. SWA analyses revealed taxon-specific effects of water deficit, with water deficit increasing SWA concentrations in young leaves of woolly loco but not affecting SWA concentration in silky crazyweed. These results suggest that the endophyte behaves as a parasite in woolly loco plants grown under optimal but not under water-limited conditions. Further, results indicate that drought conditions elevate the toxicity of woolly loco plants. Improved understanding of endophyte-locoweed interactions and factors influencing SWA levels will contribute to the development of livestock management strategies to predict toxicity in particular locoweed populations.
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- By Lenard A. Adler, Pinky Agarwal, Rehan Ahmed, Jagga Rao Alluri, Fawaz Al-Mufti, Samuel Alperin, Michael Amoashiy, Michael Andary, David J. Anschel, Padmaja Aradhya, Vandana Aspen, Esther Baldinger, Jee Bang, George D. Baquis, John J. Barry, Jason J. S. Barton, Julius Bazan, Amanda R. Bedford, Marlene Behrmann, Lourdes Bello-Espinosa, Ajay Berdia, Alan R. Berger, Mark Beyer, Don C. Bienfang, Kevin M. Biglan, Thomas M. Boes, Paul W. Brazis, Jonathan L. Brisman, Jeffrey A. Brown, Scott E. Brown, Ryan R. Byrne, Rina Caprarella, Casey A. Chamberlain, Wan-Tsu W. Chang, Grace M. Charles, Jasvinder Chawla, David Clark, Todd J. Cohen, Joe Colombo, Howard Crystal, Vladimir Dadashev, Sarita B. Dave, Jean Robert Desrouleaux, Richard L. Doty, Robert Duarte, Jeffrey S. Durmer, Christyn M. Edmundson, Eric R. Eggenberger, Steven Ender, Noam Epstein, Alberto J. Espay, Alan B. Ettinger, Niloofar (Nelly) Faghani, Amtul Farheen, Edward Firouztale, Rod Foroozan, Anne L. Foundas, David Elliot Friedman, Deborah I. Friedman, Steven J. Frucht, Oded Gerber, Tal Gilboa, Martin Gizzi, Teneille G. Gofton, Louis J. Goodrich, Malcolm H. Gottesman, Varda Gross-Tsur, Deepak Grover, David A. Gudis, John J. Halperin, Maxim D. Hammer, Andrew R. Harrison, L. Anne Hayman, Galen V. Henderson, Steven Herskovitz, Caitlin Hoffman, Laryssa A. Huryn, Andres M. Kanner, Gary P. Kaplan, Bashar Katirji, Kenneth R. Kaufman, Annie Killoran, Nina Kirz, Gad E. Klein, Danielle G. Koby, Christopher P. Kogut, W. Curt LaFrance, Patrick J.M. Lavin, Susan W. Law, James L. Levenson, Richard B. Lipton, Glenn Lopate, Daniel J. Luciano, Reema Maindiratta, Robert M. Mallery, Georgios Manousakis, Alan Mazurek, Luis J. Mejico, Dragana Micic, Ali Mokhtarzadeh, Walter J. Molofsky, Heather E. Moss, Mark L. Moster, Manpreet Multani, Siddhartha Nadkarni, George C. Newman, Rolla Nuoman, Paul A. Nyquist, Gaia Donata Oggioni, Odi Oguh, Denis Ostrovskiy, Kristina Y. Pao, Juwen Park, Anastas F. Pass, Victoria S. Pelak, Jeffrey Peterson, John Pile-Spellman, Misha L. Pless, Gregory M. Pontone, Aparna M. Prabhu, Michael T. Pulley, Philip Ragone, Prajwal Rajappa, Venkat Ramani, Sindhu Ramchandren, Ritesh A. Ramdhani, Ramses Ribot, Heidi D. Riney, Diana Rojas-Soto, Michael Ronthal, Daniel M. Rosenbaum, David B. Rosenfield, Durga Roy, Michael J. Ruckenstein, Max C. Rudansky, Eva Sahay, Friedhelm Sandbrink, Jade S. Schiffman, Angela Scicutella, Maroun T. Semaan, Robert C. Sergott, Aashit K. Shah, David M. Shaw, Amit M. Shelat, Claire A. Sheldon, Anant M. Shenoy, Yelizaveta Sher, Jessica A. Shields, Tanya Simuni, Rajpaul Singh, Eric E. Smouha, David Solomon, Mehri Songhorian, Steven A. Sparr, Egilius L. H. Spierings, Eve G. Spratt, Beth Stein, S.H. Subramony, Rosa Ana Tang, Cara Tannenbaum, Hakan Tekeli, Amanda J. Thompson, Michael J. Thorpy, Matthew J. Thurtell, Pedro J. Torrico, Ira M. Turner, Scott Uretsky, Ruth H. Walker, Deborah M. Weisbrot, Michael A. Williams, Jacques Winter, Randall J. Wright, Jay Elliot Yasen, Shicong Ye, G. Bryan Young, Huiying Yu, Ryan J. Zehnder
- Edited by Alan B. Ettinger, Albert Einstein College of Medicine, New York, Deborah M. Weisbrot, State University of New York, Stony Brook
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- Book:
- Neurologic Differential Diagnosis
- Published online:
- 05 June 2014
- Print publication:
- 17 April 2014, pp xi-xx
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14C Dating of Laminated Sediments from Loch Ness, Scotland
- M. C. Cooper, P.E. O'Sullivan, D. D. Harkness, E. M. Lawson, D. Bull, A. E. S. Kemp, Sylvia M. Peglar, Nina M. Matthews, R. I. Jones, A. J. Shine
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- Journal:
- Radiocarbon / Volume 40 / Issue 2 / 1997
- Published online by Cambridge University Press:
- 18 July 2016, pp. 781-793
- Print publication:
- 1997
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Radiometric and AMS radiocarbon dating of a 6-m sediment core from Loch Ness, Scotland, indicates that it represents perhaps the very end of the Late Pleistocene, and the first ca. 7500 yr of the Holocene. Counts of laminations observed in the Holocene section of the core suggest that they are present in sufficient number to constitute annual laminations (varves), an hypothesis consistent with the pollen record, which contains a sequence of zones representative of the Early, Middle and part of the Late Holocene regional vegetation history. On the basis of BSEM and X-ray studies of sediments, and modern seston trap data, the laminations are believed to be produced by winter floods, which introduce increased silt loading into the Loch. Sediment for the rest of the year is mostly composed of clay-sized material. This hypothesis is being further tested, however, by continuing sedimentological and microfossil studies.
Time-depth relations for the core based on calibrated 14C dates and lamination counts, respectively, illustrate the close correspondence between the two sets of data. The latter are therefore now being used to develop a varve chronology for the Holocene for Loch Ness. This will then in turn be used for further chronological studies, and for investigations of palaeoclimatic variations over the eastern North Atlantic, to which the signal of lamination thickness in the sediments is thought to be particularly sensitive. They may also eventually be used for calibration studies, employing 14C dating of specific carbon compounds, or groups of compounds extracted from the sediment using modern organic geochemical methods.